Dermatology Flashcards

Question

What meds do you use for cellulitis, folliculitis, furuncles & carbuncles?

Answer 1

Mild disease: Use oral medications: • Dicloxacillin, cephalexin, cefadroxyl • Penicillin allergic: erythromycin, clarithromycin, or clindamycin • MRSA: doxycycline, dindamycin, trimethoprim/sulfamethoxazole Severe disease (fever present): Use intravenous medications: • Oxacillin, nafcillin, cefazolin • Penicillin allergic: clindamycin,vancomycin • MRSA: vancomycin, linezolid, daptomycin, tigecycline, ceftaroline

Answer 2

occurs below the dermal - epidermal junction infection of soft tissue - affects the lower legs, skin is warm, red, swollen, and tender - unilateral erythematous plaque that poorly demarcated - more commonly caused by staph - Dx - clinical, most accurate is inject saline into skin and aspirate for culture

Answer 3

oxacillin, naficillin, cefazolin are best empiric therapy | - remember topical antibiotics will not work

Answer 4

staph infection of the hair bulb furuncle develop into a small abscess --> collection of furuncles are called carbuncles folliculitis --> furuncle --> carbuncles

Answer 5

Can be treated w warm compress w/o antibiotics - if not then use mupirocin is best choice for folliculitis and furuncles and carbuncles are treated w anti-staph antibiotics, IV for carbuncles

Answer 6

Necrotizing fasciitis - extremely severe, life threatening skin infection MC polymicrobial, DM are at increased risk Hx & PE - bullae and palpable crepitus, high fever Dx - lab evid - increased CPK, imaging shows air in tissue or necrosis confirm w surgical debridement Tx - surgery, best empiric is ampicillin/sulbactam, if strep pyo tx w clindamycin + pen

Answer 7

Paranychia - loculation under skin, surrounding nail - tx - small incision & drainage w antistaph antibiotics Chronic - nail not intact, can lose cuticle, affects women Acute - nail is intact, yellow discoloration MRSA infect - clinda oral

Answer 8

Second generation cephalosporins (cefoxitin,cefotetan,cefuroxime) • Beta-lactam/beta-lactamase combinations Amoxicillin/clavulanate - Ampicillin/sulbactam Ticarcillin/clavulanate Piperacillin/tazobactam • Carbapenems (imipenem, meropenem)

Answer 9

Fungal infection - tinea & oncomycosis Dx - initially clinical, confirmed w KOH prep KOH dissolves skin & nail but not fungus which shows fungal hyphae and yeast (balls & spagetti), if KOH + then no culture needed most accurate dx is culture Tx oncomycosis (nail infection) or tinea captis (hair) are treated with either terbinafine (12wk for toenails & 6 wk fingernail) or itraconazole; must check LFT w terbinafine other infections can be treated w ketoconazole clotrimazole, econazole, terbinafine, miconazole

Answer 10

DDx - Pitraysis vesicolor (hyperpig & hypopig lesion) = Wood light - yellow to white fluroscence DDx erythesma = bacterial infection looks like fungal Wood light = coral red caused coryn

Answer 11

antifungal

Answer 12

oral ketoconazole causes gynecomastia

Answer 13

* Penicillins * Sulfa drugs (including thiazides, furosemide, and sulfonylureas) * Allopurinol * Phenytoin * Lamotrigine * NSAIDs

Answer 14

Fixed drug reaction - localized allergic rxn that occurs within the same anatomical site on skin with repeated drug exposure MC - due aspirin, NSAID, tetracy, barb Hx & PE - shar demarcated lesion leaving hyperpigmentation spot after resolution Tx - d/c drug & treat w topical sterioids

Answer 15

Skin stays intact without mucous mem- brane1involvement. No specific therapy.

Answer 16

widespread, small "target" lesions; most are on the trunk. occurs in 7 days of infection No mucous membrane involvement. May also be from herpes or mycoplasma. Hx & PE = erythema w central vesicles palms and soles, involves lips & buccal mucosal Tx - antihistamine

Answer 17

involves the mucous membranes. Sloughs off respiratory epithelium and may lead to respiratory failure. <10-15% of total body surface area, usually involves face & body, Tx - withdraw offending agent, supportive care & mechanical ventilation Steroids not clearly beneficial. Use intravenous immunoglobulins (IVIG)

Answer 18

> 40-50%, more serious and severe, drug induced, Dx - biopsy reveals epidermal necrosisSepsis is MCC of death, prophylactic antibiotic systemic antibiotics - rash with mucous membrane involvement and adds Nikolsky sign. Steroids definitely do not help. Treat with IVIG.

Answer 19

TEN - exotoxin mediated illness caused by either Group A strep or s. aureus RFs = DM, alcohol, single tampon use, surgery Hx & PE = fever, hypotension, diffuse rash Criteria = fever >38.9, diffuse macular erythroderma - desquamation 1-2 wk after rash, hypotension >3 organs involved Dx - clinically Tx - clindamycin + ticarillin/clavulanate or pipercillin/tazobactam (IV) if staph - clinda + vanco

Answer 20

+ Nikolsky sign treatment w supportive care and anti-staphy (oxacillin or nafcillin) - drugs don't reverse the disease but kill staph

Answer 21

``` Decubitus Ulcers - chronic sores occuring in the pressure areas of body where bone is closer to skin, pts who are bedridden Hx & PE - nonblanchable reddness —> destruction of superificial epidermis —> destruc all the way to bone Dx - surgical debridement Tx - relieve pressure if still there then antibiotics ```

Answer 22

Erythema Nodosum - localized inflammatory condition of skin secondary to recent infection assoc w pregnancy, strep infection, coccidiomycosis, histoplasmosis, sarcoidosis, IBD, syphillus or hepatits Hx & PE - multiple painful red raised nodules on anterior surface of lower ext, lasting 6 wks Dx - ASLO titers show recent strep infection if no etiology in hx Tx - treat underlining condition & analgesics - NSAIDS and potassium iodide solution respond to treatment

Answer 23

Alopecia Acreata - autoimmune disease - Ab’s attack hair follicles and destroy hair production Tx - resolves spont; immediate therapy is steroid injection

Answer 24

Rosacea - chronic inflam condition that causes flushing w burning sensation most common manifestations are flushing, dilated prominent telangiectases (primarily on the face), persistent facial erythema Etio = exaggerated vasodilatory response to increased temperature, and redness can be easily exacerbated by hot drinks and hot baths or showers RF = lighter skin, hot showers, extreme climate Hx & PE = flushing, nontransient erythema, dome shaped red papules & pustules phyma - distinct swelling caused by lymphedema and hypertrophy of subcut skin Dx - clinically Tx - avoid topical steriods, telangiectasia tx w ablation oral tetracycline/topical metro/oral erythromycin

Answer 25

Pemphigus vulgaris is an autoimmune disease of unclear etiology in which the body essentially becomes allergic to its own skin. Antibodies are produced against antigens in the intercellular spaces of the epidermal cells. Etio - Pemphigus vulgaris is most often idiopathic, but ACE inhibitors or penicillamine can occasionally cause it.

Answer 26

Vulgaris occurs in patients age 30s and 40s Pemphigus vulgaris is a much more serious and potentially life- threatening disease than pemphigoid. Vulgaris occurs prominently in the mouth and often starts there. The oral lesions are erosions, not bullae. The bullae are very thin and flaccid and break easily. This leads to the loss of large volumes of skin surface area, so it acts like a burn. pemphigus vulgaris are painful, not pruritic.

Answer 27

The presence of the Nikolsky sign (the easy removal of skin by just a little pressure from the examiner’s finger, pulling the skin off like a sheet) pemphigus vulgaris, staphylococcal scalded skin syndrome, and toxic epidermal necrolysis.

Answer 28

The most accurate diagnostic test is to biopsy the skin and to use immunofluorescent stains. These stains will detect intercellular deposits of IgG and C3 in the epidermis.

Answer 29

Treatment is with systemic glucocorticoids, such as prednisone. For those in whom steroids are ineffective or not tolerated, you can use azathioprine, mycophenolate, or cyclophosphamide. Rituximab and IVIG are also effective.

Answer 30

Pemphigoid is 2× as common as pemphigus vulgaris and occurs in elderly persons age 70s and 80s. It can also be drug induced with sulfa drugs, including furosemide, penicilla- mine, and others.

Answer 31

The defect occurs at the dermo-epidermal junction, so the layer of skin that separates off is much thicker. Hence, there is much less fluid loss, and infection is much less likely as compared with pemphigus vulgaris. less mortality

Answer 32

The most accurate diagnostic test is a biopsy with immunofluorescent antibodies at the dermo-epidermal junction (basement membrane).

Answer 33

Systemic steroids, such as prednisone, are the standard means of treatment. Tetracycline or erythromycin combined with nicotinamide is the alternative to steroids. Use topical steroids only if no oral lesions are present.

Answer 34

Porphyria cutanea tarda is a disorder of porphyrin metabolism. Deficiency of the enzyme uroporphyrinogen decarboxylase results in an abnormally high accumulation of porphyrins, which then leads to a photosensitivity reaction. - The test question should give a history of HIV, alcoholism, liver disease, chronic hepatitis C, or a woman taking oral contraceptives. - porphyria cutanea tarda is associated with increased liver iron stores - Diabetes is found in 25% of patients.

Answer 35

Fragile, nonhealing blisters are seen on the sun-exposed parts of the body, such as the backs of the hands and the face. This leads to hyperpigmentation of the skin in general and hypertrichosis of the face.

Answer 36

The diagnostic test is a level of urinary uroporphyrins. Uroporphyrins are elevated 2–5× above the coproporphyrins in this disease.

Answer 37

The best initial step in management is to stop drinking alcohol (although it is unlikely to be effective) and to discontinue all estrogen use - Combine treatment with barrier sun protection, such as clothing, because most sunscreens do not seem to block the wavelength of light causing the dermal reaction. - The most effective therapy to use if this is insufficient is phlebotomy to remove iron. - Deferoxamine is used to remove iron if phlebotomy is not possible - antimalarial drug chloroquine increases the excretion of porphyrins.

Answer 38

Acute urticaria is a hypersensitivity reaction most often mediated by IgE and mast cell activation, resulting in evanescent wheals and hives. It is a type of localized, cutaneous anaphylaxis, but without the hypotension and hemodynamic instability. - The most common causes of acute urticaria are allergic reactions to medications, insect bites, and foods, and occasionally, the result of emotions. - The most common medications are aspirin, NSAIDs, morphine, codeine, penicillins, phenytoin, and quinolones. ACE inhibitors are also associated with urticaria, as well as angioedema - most common foods are peanuts, shellfish, tomatoes, and strawberries. Contact with latex in any form can also cause urticaria.

Answer 39

Acute urticaria lasts 6 weeks in duration and is associated with pressure on the skin, cold, or vibration. In patients with chronic urticaria lasting >6 weeks, you should investigate the etiology.

Answer 40

Urticaria is treated with H1 antihistamines. Severe, acute urticaria is treated with older medications, such as diphenhydramine (Benadryl), hydroxyzine (Atarax), or cypro- heptadine. If it is life-threatening, use H2 antihistamines when H1 antihistamines fail and add systemic steroids. - Chronic therapy is with newer, nonsedating antihistamines, such loratadine, desloratadine, fexofenadine, or cetirizine - Astemizole and terfenadine should never be used and are no longer marketed;

Answer 41

A morbilliform rash is a milder version of a hypersensitivity reaction compared with urticaria. This is the “typical” type of drug reaction and is lymphocyte mediated.

Answer 42

The rash resembles measles and is usually secondary to medications that the patient is allergic to, such as penicillin, sulfa drugs, allopurinol, or phenytoin. It is a general- ized, maculopapular eruption that blanches with pressure. - rxn can appear few days after exposure or after meds have been stopped.

Answer 43

Antihistamines are effective

Answer 44

Although erythema multiforme (EM) may be caused by the same types of medications that cause urticaria and morbilliform rashes (penicillins, phenytoin, NSAIDs, and sulfa drugs), - the most common cause of EM is a reaction to infection. The majority of cases follow infection with herpes simplex or Mycoplasma.

Answer 45

The most characteristic feature of EM is target-like lesions that occur especially on the palms and soles. These lesions can also be described as “iris-like.” Bullae are not uniformly found. EM of this type usually does not involve mucous membranes.

Answer 46

antihistamines and by treating the underlying infection.

Answer 47

Stevens-Johnson syndrome (SJS) is sometimes called erythema multiforme major. - It is sometimes difficult to distinguish SJS from toxic epidermal necrolysis (TEN) and, in fact, the two diseases may be considered a spectrum of severity of the same disorder. - All of these disorders may arise as a hypersensitivity response to the same set of medications, such as penicillins, sulfa drugs, NSAIDs, phenytoin, and phenobarbital.

Answer 48

SJS usually involves <5 to 10%. There is mucous-membrane involvement in 90% of cases, most often of the oral cavity and the conjunctivae, although there may be extensive involve- ment of the respiratory tract.

Answer 49

These patients should be treated with early admission to a burn unit, withdrawal of the offending drug, and supportive care. Respiratory-tract involvement may be so severe as to require mechanical ventilation. - The best initial therapy for severe disease is intravenous immunoglobulins. Other therapies of unclear value are cyclophosphamide, cyclosporine, and thalidomide.

Answer 50

Toxic epidermal necrolysis (TEN) is the most serious version of a cutaneous hypersensitivity reaction. Mortality may be as high as 40 to 50%.

Answer 51

Much more of the body surface area (BSA) is involved and may range from 30 to 100%. The Nikolsky sign is present, and the skin easily sloughs off. TEN has certain features similar to staphylococcal scalded skin syndrome; however, TEN is drug induced as opposed to being caused by a toxin coming from an organism.

Answer 52

The diagnosis is usually clinical. The most accurate diagnostic test is a skin biopsy, which will reveal full thickness epidermal necrosis. A skin biopsy is usually not necessary.

Answer 53

Sepsis is the most common cause of death, but prophylactic systemic antibiotics are not indicated. Systemic steroids are not effective and may, in fact, decrease survival.

Answer 54

This is a localized allergic drug reaction that recurs at precisely the same anatomic site on the skin with repeated drug exposure - The most commonly implicated drugs include aspirin, NSAIDs, tetracycline, and barbiturates.

Answer 55

Fixed drug reactions are generally round, sharply demarcated lesions that leave a hyperpigmented spot at the site after they resolve.

Answer 56

In addition to discontinuation of the offending drug, the reactions can be treated with topical steroids.

Answer 57

``` Erythema nodosum (EN) is a localized inflammatory condition of the skin or panniculitis. It is secondary to recent infections or inflammatory conditions. It is also associated with pregnancy. MC infections that cause EN - strep - coccidioidomycosis - histoplasmosis - sarcoidosis - IBD - syphilus - TB - hepatitis - enteric infections (yersinia) ```

Answer 58

Erythema nodosum consists of multiple painful, red, raised nodules on the anterior surface of the lower extremities. They are extremely tender to palpation. They do not ulcerate, and they generally last about 6 weeks.

Answer 59

ASLO titers can help determine who has recently had a streptococcal infection if there is no other etiology apparent from the history.

Answer 60

Therapy consists of treating the underlying disease, as well as the use of analgesics and NSAIDs. Potassium iodide solution can be used in those who do not respond to symptom- atic therapy. Erythema nodosum is usually a self-limiting condition.

Answer 61

Tinea pedis, cruris, corporis, versicolor, capitis, and onychomycosis

Answer 62

“Superficial fungal infections” refer to those infections limited to the skin, nails, and hair. Remember, though, that these answers would not be valid for more deep-seated, life-threatening infections, such as fungal endocarditis, meningitis, or abscesses.

Answer 63

All superficial fungal infections of the skin, hair, and nails are primarily diagnosed by their visual appearance and confirmed by a potassium hydroxide (KOH) test of the skin. - KOH has the ability to dissolve the epithelial cells and collagen of the nail, but does not have the ability to melt away the fungus. Hence, a KOH preparation gives an immediate diagnostic answer by revealing fungal hyphae. This is particularly characteristic in tinea versicolor, where the Malassezia furfur (Pityrosporum orbiculare) organism appears in a “spaghetti and meatballs” pattern. - most accurate test is to culture the fungus.

Answer 64

For onychomycosis (nail infection) or hair infection (tinea capitis), the medications with the greatest efficacy are oral terbinafine or itraconazole. - These medications are used for at least 6 weeks for fingernails and 12 weeks for toenails. Terbinafine is potentially hepatotoxic, and it is important to periodically check liver function tests. - Griseofulvin must be used for 6 to 12 months in the treatment of fingernails and has much less antifungal efficacy than terbinafine. - Griseofulvin is no longer recommended in the treatment of oncomycosis of the toenails. In the treatment of tinea capitis, griseofulvin is recommended for 6 to 8 weeks - All of the other fungal infections of the skin that don’t involve the hair or nails may be treated with any of the following topical medications: ketoconazole, clotrimazole, econazole, terbin- afine, miconazole, sertaconazole, sulconazole, tolnaftate, or naftifine.

Answer 65

Ketoconazole has more adverse effects when used systemically, such as hepatotoxicity and gynecomastia. There is no topical form of fluconazole.

Answer 66

Antifungal medications generally should not be used in combination with topical steroids, unless a diagnosis has been confirmed. Steroids in a cream can relieve redness and itching and give the appearance of improvement even in impetigo and contact dermatitis.

Answer 67

Skin infection characterized by multiple macules (usually asymptomatic), varying in color from white to brown. - Pityrosporum orbiculare (Malassezia furfur).

Answer 68

Tan, brown, or white scaling macular lesions that tend to coalesce; found on chest, neck, abdomen, or face. Lesions do not tan. - Skin scrapings examined with 10% KOH under a microscope. The classic descrip- tion is of “spaghetti and meatballs,” which refers to the hyphae and spores that can be seen in the KOH prep. - Topical selenium sulfide, clotrimazole, ketoconazole, or oral itraconazole. The need for local or systemic therapy is decided on the basis of the amount of surface area involved

Answer 69

the main difference in the use of topical selenium sulfide every 2-3 wk vs oral therapy w/ itraconazole or fluconazole because tinea vesicolor tends to involve large amounts of body surface area and difficult to cover this amount of skin w topical cream or lotion

Answer 70

A yeast infection usually involving skin and mucous membranes, but it can also be systemic. - Candida albicans. Usually spreads in patients with decreased host defenses. Patients with any of the following have an increased susceptibility: systemic antibacterial therapy, obe- sity, diabetes mellitus, corticosteroid or antimetabolite therapy, pregnancy, debilitating disease and blood dyscrasias, or HIV.

Answer 71

- Intertriginous infection: Well demarcated, erythematous, itchy, exudative patches, usually rimmed with small red-based pustules that occur in the groin, gluteal folds (diaper rash), axilla, umbilicus, and infra mammary areas. - vulvovaginitis: white or yellow d/c w/ inflammation of vag wall and vulva. Common in pregnant women and patients with diabetes mellitus. - oral candidiasis - thrush - white patches of exudates on tongue or buccal mucosa - candidal paronychia - painful swelling around the nail

Answer 72

Potassium hydroxide on slide to visualize fungal forms. Culture is definitive.

Answer 73

- topical nystatin, clotrimazole, miconazole, ciclopirox, econazole, terconazole systemic amphotericin in serious invasive infections. Fluconazole in less serious infections. - Candida paronychia requires systemic therapy.

Answer 74

Staph & Strep

Answer 75

Antibiotics used to treat Staphylococcus are dicloxacillin, cephalexin (Keflex), or cefadroxil (Duricef). Cefadroxil, cefazolin, or cephalexin are the preferred agents. - The intravenous equivalents of oral dicloxacillin include oxacillin and nafcillin. The intravenous equivalent of cefadroxil is cefazolin.

Answer 76

if the penicillin reaction is anaphylaxis then cephalosporins cannot be used. The alternative antibiotics that will treat the skin are macrolides, such as erythromycin, azithromycin, clarithromycin, or the newer fluoroquinolones (levofloxacin or moxifloxacin).

Answer 77

Oral therapy for MRSA is with clindamycin, TMP/SMX, or doxycycline. The ultimate form of oral MRSA therapy is linezolid

Answer 78

A superficial, pustular skin infection, seen mainly in children (ecthyma is an ulcer- ative form of impetigo), with oozing, crusting, and draining of the lesions. It is a superficial bacterial infection of the skin largely limited to the epidermis and not spreading below the dermal-epidermal junction. - caused by Group A beta-hemolytic Streptococcus and S. aureus (bullous impetigo)

Answer 79

- limited to epidermis - the patient history will describe the infection with words such as “weeping,” “oozing,” “honey colored,” or “draining.” Impetigo occurs more often in warm, humid conditions, particularly when there is poverty and crowding of children. - More common on arms, legs, and face. May follow trauma to skin. Begins as maculopapules and rapidly progresses to vesicular pustular lesions or bullae. - The crusts are described as having a golden or yellow appearance and if untreated can progress to lymphangitis, furunculosis, or cellulitis, and acute glomerulonephritis. Impetigo may cause glomerulonephritis,

Answer 80

oral 1st gen cephalosporin or semisynthetic penicillin - oxacillin, cloxacillin, dicloxacin (wide spread cases) - topical mupirocin, bacitracin, retapamulin (more active against staph and strep) for mild cases - penicillin- allergic pts treat w macrolides (clarithromycin or azithromycin) - TMP/SMZ, clindamycin, doxy for MRSA

Answer 81

Erysipelas is a bacterial infection of a deeper layer of the skin than impetigo. Erysipelas involves both the dermis and epidermis and is most commonly caused by group A Streptococcus (pyogenes).

Answer 82

Because it involves lymphatic channels in the dermis, erysipelas is more likely to result in fever, chills, and bacteremia. It often involves the face, giving a bright red, angry, swollen appearance. Usually bilateral, shiny red, indurated edematous tender lesions on the face, arms, and legs.

Answer 83

Semisynthetic penicillin or first-generation cephalosporin if you cannot distinguish it from cellulitis; penicillin (if Streptococcus is certain)

Answer 84

Cellulitis is a bacterial infection of the dermis and subcutaneous tissues with Staphylococcus and Streptococcus. - Cellulitis is characterized by redness, swelling, and warmth and tender- ness of the skin. Because it is below the dermal-epidermal junction, there is no oozing, crusting, weeping, or draining.

Answer 85

Cellulitis is treated with the antibiotics prescribed for erysipelas on the basis of the severity of the disease. If there is fever, hypotension, or signs of sepsis or if oral therapy has not been effective, then the patient should receive intravenous therapy. - Oxacillin, nafcillin, or cefazolin is the best therapy. Treatment is generally empiric because injecting and aspirating sterile saline for a specific microbiologic diagnosis has only a 20% sensitivity. Oral therapy for MRSA is with clindamycin, TMP/SMX, or doxycycline.

Answer 86

Folliculitis, furuncles, and carbuncles represent 3 degrees of severity of staphylococcal infections occurring around a hair follicle. Occasionally, folliculitis can be the result of those who contract Pseudomonas in a whirlpool or from a hot tub.

Answer 87

As folliculitis worsens from a simple superficial infection around a hair follicle, it becomes a small collection of infected material known as a furuncle. When several furuncles become confluent into a single lesion, the lesion becomes known as a carbuncle, which is essentially a localized skin abscess. Folliculitis is rarely tender, but furuncles and carbuncles are often extremely tender.

Answer 88

Folliculitis mainly can be treated with warm compresses locally without the need for antibiotics. If antibiotics are required, mupirocin is the best choice. - Furuncles and carbuncles require treatment with systemic anti-staphylococcal antibiotics, and in the case of carbuncles, should be administered intravenously. Treatment with dicloxacillin, cephalexin, or cefadroxyl is acceptable. A large furuncle or carbuncle will also require surgical drainage.

Answer 89

Necrotizing fasciitis is an extremely severe, life-threatening infection of the skin. It starts as a cellulitis that dissects into the fascial planes of the skin. Streptococcus and Clostridium are the most common organisms because they are able to produce a toxin that further worsens the damage to the fascia. Diabetes increases the risk of developing fasciitis.

Answer 90

The features that distinguish necrotizing fasciitis from simple cellulitis are a very high fever, a portal of entry into the skin, pain out of proportion to the superficial appearance, the presence of bullae, and palpable crepitus

Answer 91

Laboratory evidence of necrotizing fasciitis is an elevated creatine phosphokinase and an x-ray, CT scan, or MRI that show air in the tissue or necrosis. - Surgical debridement is the best way to confirm the diagnosis and is also the mainstay of therapy.

Answer 92

Surgery is the mainstay of therapy. The best empiric antibiotics are the beta-lactam/ beta-lactamase combination medications, such as ampicillin/sulbactam (Unasyn), ticarcillin/ clavulanate (Timentin). If there is a definite diagnosis of group A Streptococcus (pyogenes), then treat with clindamycin and penicillin. Without adequate therapy, necrotizing fasciitis has an 80% mortality rate.

Answer 93

Paronychia is an infection loculated under the skin surrounding a nail. It is generally treated with a small incision to allow drainage and with antistaphylococcal antibiotics. The antistaphy- lococcal antibiotics are dicloxacillin, cefadroxil, or cephalexin orally, or oxacillin, nafcillin, or cefazolin intravenously

Answer 94

Herpes simplex infections of the genitals are characterized by multiple, painful vesicles. - The vesicles are usually obvious by examination, and antibiotic therapy should be initiated immediately without waiting for results of the tests.

Answer 95

This is done with active lesions only. In the event that the diagnosis is not clear or the lesions have become confluent into an ulcer, the best initial test is a Tzanck smear. The Tzanck smear is somewhat nonspecific in that it will determine only that the infection is in the herpes- virus family. Tzanck smears detect multinucleated giant cells and are similar in technique to a Pap smear. - The most accurate diagnostic test is a viral culture, which will grow in 24 to 48 hours. Serology is not a useful test for diagnosing herpes infections.

Answer 96

Immediate therapy is with oral acyclovir, famciclovir, or valacyclovir. Topical acyclo- vir has extremely little efficacy; it will slightly improve resolution in primary lesions and will do absolutely nothing for recurrent herpes simplex lesions. - Topical penciclovir has some use for oral herpetic lesions, but it must be applied every 2 hours. The treatment of acyclovir-resistant herpes is with foscarnet.

Answer 97

Chickenpox is primarily a disease of children. Complications of varicella are pneumonia, hepatitis, and dissemination. Episodes of dermatomal herpes zoster, also known as shingles, occur more frequently in the elderly and in those with defects of the lymphocytic portion of the immune system (i.e., leukemia, lymphoma, HIV, or those on steroids).

Answer 98

The vesicles are 2 to 3 mm in size at all stages of development and are on an erythematous base. - Dx = Although the Tzanck prep and viral culture are the best initial and most accurate diagnostic tests, they are generally not necessary because little else will produce a band of vesicles in a dermatomal distribution besides herpes zoster.

Answer 99

If the child is immunocompromised or the primary infection occurs in an adult, then acyclovir, valacyclovir, or famciclovir should be given. - Steroid use is still not clearly beneficial, although the best evidence for efficacy is in elderly patients with severe pain. The rapid administration of acyclovir still has the best efficacy for decreasing the risk of postherpetic neuralgia. - The most effective analgesic specific for postherpetic neuralgia is gabapentin. - Nonimmune adults exposed to chickenpox should receive varicella zoster immunoglobulin within 96 hours of the exposure in order for it to be effective.

Answer 100

- Skin-colored, waxy, umbilicated papules. - etio = Poxvirus - presentation = Small papules that appear anywhere on the skin (genital and pubic area), usually by venereal contact, and are asymptomatic. The lesions have a central umbilication. They can be transmitted by skin-to-skin contact or sexually. Commonly seen in children; frequency is increased severalfold in patients infected with HIV

Answer 101

Dx - mainly on appearance; lab testing is rarely necessary Giemsa stain - large cells with inclusion bodies Tx - freezing, curettage, electrocautery or cantharidin

Answer 102

Scabies involves vesicular eruptions resulting from the females of the Sarcoptes scabiei (hominis) burrowing into the skin. - A parasitic skin infection characterized by superficial burrows, intense pruritus, and secondary infections. - Itch mite, Sarcoptes scabiei. Transmitted by skin-to-skin contact.

Answer 103

Scabies primarily involves the web spaces of the hands and feet. It also produces pruritic lesions around the penis, breasts, and axillary folds. Itching can be extreme. - Because Sarcoptes scabiei is quite small, all that can be seen with the naked eye are the burrows and excoriations around small pruritic vesicles. Scabies often spares the head. - affects HIV or immunocompromised are particularly vulnerable to an extremely exuberant form of scabies with severe crusting and malodorousness, known as Norwegian scabies

Answer 104

The diagnosis in all cases is confirmed by scraping out the organism after mineral oil is applied to a burrow; however, skin scrapings are usually not necessary and are not routinely done.

Answer 105

Scabies can be successfully treated with permethrin. Lindane (Kwell) has equal efficacy, but also greater toxicity. Lindane should not be used in pregnant women. Ivermectin is a suitable alternative and is given as oral therapy if the disease is extensive. Treat Norwegian scabies with a combination of permethrin and ivermectin.

Answer 106

``` Skin infestation by lice. - Head Pediculus humanus capitis - Body Pediculus humanus corporis - Phthirus pubis (“crablouse”) Clinical present - Itching, excoriations, erythematous macules and papules, and sometimes secondary bacterial infection. ```

Answer 107

Direct examination of the pubic area, axillae, scalp, and other hair-bearing surfaces for the organism (louse or nits). - Tx - Permethrin, lindane (Kwell)

Answer 108

This disorder is a systemic reaction to a toxin produced from Staphylococcus attached to a foreign body. The majority of cases now are not from a menstrual source, such as a tampon or vaginal packing. Nasal packing, retained sutures, or any other form of surgical material retained in the body can promote the growth of the type of staphylococci that produces the toxin.

Answer 109

Because there is no single specific test, cases are matters of definition. The definition of a case of toxic shock syndrome is the presence of 3 or more or of the following findings: fever >102°F, a systolic blood pressure <100,000. - In addition, toxic shock is a systemic disease that also raises the creatinine, creatine phosphokinase (CPK), and liver function tests; lowers the platelet count; and can cause central nervous system dysfunction, such as confusion. - hypo Ca usually because of a diffuse capillary leak syndrome that drops the albumin level

Answer 110

Empiric treatment is with plus vancomycin until cultures return. - In confirmed cases of methicillin sensitive strains, treatment should be with clindamycin plus an antistaphylococcal medication (oxacillin, nafacillin). - In methicillin resistant strains (MRSA), either vancomycin or linezolid can be used

Answer 111

Staphylococcal scalded skin syndrome (SSSS) is transmitted through physical contact with surroundings. It most commonly occurs in infants and young children and in the immunocompromised. - SSSS is mediated by a toxin from Staphylococcus. The major presenta- tion is the loss of the superficial layers of the epidermis in sheets. Nikolsky sign is present. It is markedly different from toxic shock syndrome in that there is normal blood pressure and no involvement of the liver, kidney, bone marrow, or central nervous system -

Answer 112

Patients should be managed in a burn unit and given oxacillin or other antistaphylococcal antibiotics. Vancomycin can be added because of the possibility of MRSA.

Answer 113

Benign lesions, such as the junctional or intradermal nevus, do not grow in size and have smooth, regular borders with a diameter usually <1 cm. In addition, they are homogenous in color, and this remains constant. - biopsy is most accurate method

Answer 114

This is a benign condition with hyperpigmented lesions occurring in the elderly. Seborrheic keratosis has no malignant potential and no relation to either actinic keratosis or seborrheic dermatitis. - The lesions have a “stuck on” appearance and are most common on the face shoulders, chest, and back.

Answer 115

They are removed only for cosmetic purposes with liquid nitrogen or curettage.

Answer 116

Actinic keratosis presents with precancerous lesions occurring on sun-exposed areas of the body in older persons. The lesions occur more often in those with light skin color. They contain chromosomal abnormalities, and although only 1:1,000 lesions progresses to squamous cell cancer, an individual patient may have dozens of them. Hence, the rate of trans- formation to squamous cell cancer is 0.25% per patient. - Although the lesions are usually asymptomatic, they can be tender to the touch and lighter in color.

Answer 117

Therapy is universally with sunscreen to prevent progression and recurrence. In addition, the lesions should be removed with cryotherapy, topical 5 fluorouracil (5-FU), imiquimod, topical retinoic-acid derivatives, or even curettage.

Answer 118

Superficial spreading melanoma is the most common type of malignancy, accounting for two-thirds of cases. The rate of occurrence of melanoma is rising faster than any other cancer in the United States. - Malignant lesions grow in size, have irregular borders, are uneven in shape, and have inconsistent coloring. Lentigo maligna melanoma arises on sun-exposed body parts in the elderly. Acral-lentiginous melanoma arises on the palms, soles of feet, and nail beds. - Biopsy diagnosis is best performed with a full-thickness sample because tumor thickness is by far the most important prognostic factor.

Answer 119

Melanoma is removed by excision.The size of the margin is determined by the thickness of the tumor. - Melanoma in situ needs only a 0.5-cm margin, with a 1.0-cm margin for those lesions 2 mm in depth get 2- to 3-cm margins. - There is no definitive chemotherapy for any form of skin cancer. Interferon seems to reduce recurrence rates.

Answer 120

Develops on sun-exposed skin surfaces in elderly patients. - Hx & PE = t is particularly common on the lip, where the carcinogenic potential of tobacco is multiplicative. Ulceration of the lesion is common. Metastases are rare (3–7%). Dx - biopsy Tx - surgical removal; radiotherapy

Answer 121

Sixty-five to eighty percent of all skin cancers are basal cell. (10–25% percent are squamous cell.) - Shiny or “pearly” appearance. Rate of metastases is <0.1%. - Dx - Confirmed by shave or punch biopsy. - Tx - Surgical removal. Mohs microsurgery has the greatest cure rate. In this technique, instant frozen sections are done to determine when enough tissue has been removed to give a clean margin. 5-FU can be used in treatment of superficial lesions

Answer 122

- Human herpes virus 8 is the causative organism. - These are purplish lesions found on the skin, predominantly of patients with HIV and CD4 counts <100/mm3. - Antiretroviral therapy to raise the CD4 count. When that does not occur, the specific chemotherapy for Kaposi sarcoma is liposomal doxorubicin hydrochloride or vinblastine.

Answer 123

- The etiology of psoriasis is unknown. - clincial presentation = Silvery scales develop on the extensor surfaces. It can be local or enor- mously extensive. Nail pitting is a common accompaniment. The Koebner phenomenon is the development of lesions with epidermal injury

Answer 124

Salicylic acid is used to remove heaped-up collections of scaly material so that the other therapies can make contact. If the disease is relatively localized, topical steroids are used. Severe disease also needs coal tar or anthralin derivatives. - To avoid the long-term use of steroids, which can cause skin atrophy, and to avoid coal tars, which are messy to use, substitute topical vitamin D and vitamin A derivatives. - The vitamin D derivative most frequently used is calcipotriene. Tazarotene is a topical vitamin A derivative. - All patients should use emollients such as Eucerin, Lubriderm, Aquaphor, Vaseline, or mineral oil. - newest therapy is immunomodulatory biologic agents, such as alefacept, efalizumab, etanercept, and infliximab. These are monoclonal antibodies that target defects in the immune system, such as tumor necrosis factor.

Answer 125

- Atopic dermatitis is an extraordinarily pruritic disorder characterized by high IgE levels. - Red, itchy plaques appear on the flexor surfaces. In children, lesions are common on the cheeks and scalp. Adults present with lichenification.

Answer 126

- Preventive therapy is achieved by keeping the skin moist with emollients, avoiding hot water and drying soaps, and using only cotton clothes because these patients are extremely sensitive to drying. - Active disease is managed with topical steroids, antihistamines, coal tars, and phototherapy. - Antistaphylococcal antibiotics are used if there is impetiginization of the skin. Topical immunosuppressants, such as tacrolimus and pimecrolimus, can be used to decrease dependence on steroid use. Every effort must be made to avoid scratching. The topical tricyclic doxepin can be used to help stop pruritus.

Answer 127

An oversecretion of sebaceous material and a hypersensitivity reaction to a superficial fungal organism, Pityrosporum ovale, underlie seborrheic dermatitis. - These patients present with “dandruff,” which may also occur on the face. Scaly, greasy, flaky skin is found on a red base on the scalp, eyebrows, and in the nasolabial fold.

Answer 128

Therapy consists of low-potency topical steroids, such as hydrocortisone, or topical used as a shampoo.

Answer 129

Stasis dermatitis is a hyperpigmentation built up from hemosiderin in the tissue. It occurs over a long period, from venous incompetence of the lower extremities leading to the microscopic extravasation of blood in the dermis. - Tx - There is no way to reverse this problem. Prevention of progression is with elevation of the legs and lower-extremity support hose.

Answer 130

Contact dermatitis is a hypersensitivity reaction to soaps, detergents, latex, sun- screens, or neomycin over the area of contact. Jewelry is a frequent cause, as is contact with the metal nickel from belt buckles and wristwatches. - It can occur as linear, streaked vesicles, particularly when it is from poison ivy. - Dx - A definitive diagnosis can be determined with patch testing. Tx - Identify the causative agent and treat with antihistamines and topical steroids.

Answer 131

Pityriasis rosea is a pruritic eruption that begins with a “herald patch” 70 to 80% of the time. It is mild, self-limited, and usually resolves in 8 weeks without scarring. - It is erythematous, salmon colored, and looks like secondary syphilis, except that it spares the palms and soles and has a herald patch. The lesions on the back appear in a pattern like a Christmas tree (if the observer is especially imaginative). Dx - The VDRL/RPR is negative. This is a clinical diagnosis. Tx - Very itchy lesions may be treated with topical steroids.

Answer 132

Decubitus ulcers are chronic sores that occur in the pressure areas of the body, where bone is closer to the skin. It is often associated with patients who are immobilized or bedridden. - Stage I lesions - consist of nonblanchable redness - Stage II lesions - result in destruction of the superficial epidermis or partial destruction of the dermis - Stage III lesions - have destroyed the full thickness of the skin, but not the fascia - Stage IV lesions - show destruction all the way to the bone.

Answer 133

Never culture a swab of the superficial ulcer or drainage from the ulcer. It will be impossible to determine whether it is a genuine infection or simply colonization. A definitive microbiologic diagnosis is often obtained only in the operating room after debridement. - The major theme of management is to relieve pressure. If the lesions are definitely infected, then antibiotics are useful.

Answer 134

- This is an autoimmune disease in which antibodies attack the hair follicles and destroy hair production. - The majority will resolve spontaneously over time. Immediate therapy is with local- ized steroid injection into the area of hair loss.

Answer 135

This is the loss of hair in response to an overwhelming physiologic stress, such as cancer or malnutrition. - The management is to correct the underlying stress or disease.

Answer 136

The contributing organism is Propionibacterium acnes. Pustules and cysts occur, which rupture and release free fatty acids, which in turn causes further irritation. Acne is more common in girls, but boys have more severe disease. - There are both closed comedones, which are white, and open comedones, which are black. The discharge, although purulent, is odorless.

Answer 137

Mild disease is treated with topical antibiotics, such as clindamycin, erythromycin, or sulfacetamide. In addition, the bacteriostatic agent benzoyl peroxide is used. Topical reti- noids are applied if the attempts to control the load of bacteria locally are ineffective. - Moderate disease treatment combines benzoyl peroxide with the retinoids tazarotene, tretinoin, and adapalene. Severe cystic acne is treated with oral antibiotics, such as minocycline, tetracy- cline, clindamycin, and oral isotretinoin. Oral retinoic-acid derivatives are a strong teratogen

Dermatology Flashcards

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