Flashcards in Case 32 Deck (76):
Acute urticaria case:
5 yo F with family hx of atopy who presents with an evanescent rash on her arms, legs and trunk that is sometimes pruritic. On PE, the rash is erythematous and slightly edematous. There are multiple plaques with surrounding clearing and some wheals. Patient advised to avoid potential allergens, and given antihistamine for symptomatic relief.
Seborrheic dermatitis case:
3 mo F evaluated for scalp lesion. PE reveals waxy yellow scale and mild erythema.
Followed for acne:
16 yo M. Despite trying OTC benzoyl peroxide and prescription tretinoin and clindamycin, he still has open and closed comedones, papules and pustules. He is given a prescription for a three-month trial of doxycycline.
Chronic contact dermatitis:
13 yo M with a three week history of rash below his belly button. On PE, a raised, erythematous, scaly plaque, about 4 cm in length, and 2-3 cm in width is noted in periumbilical region. It appears that he is allergic to the nickel in the buttons of his new jeans. Given appropriate counseling.
Girl with history of severe eczema recently exposed to lice. Mother wants to know if she should pick up daughter from school and bring her in from treatment right away. Suitable counseling regarding etiology and treatment of lice.
13 month old male who developed a rash over the past week. PE reveals pustular eruption on his trunk, palms and soles. Further questioning reveals that Johnny and both his parents have been itchy. Exam reveals linear lesions between the mothers liners and along the father's abdomen. The family is diagnosed and given permethrin.
Young mother worried about ringworm in her child and her horse recently having worms too. Etiology and treatment of ringworm is discussed, and the student learns about the other forms of tine as well.
What is the classification of mild acne?
Comedonal acne with perhaps a few papules or pustules.
What is the classification of moderate acne?
Significant inflammatory lesions that may leave scars.
What is the classification of severe acne?
Nodulo-cystic type carries an even higher risk for significant scarring.
Pediculosis capitis (lice):
-Commonly seen among school children because of close personal contact and shared belongings
-Not related to personal hygiene habits
-Nits are the egg cases of lice. They are firmly attached to the hair shaft 1-2 mm from the scalp and difficult to remove.
-Classic lesion: 5-10 mm linear thread-like lesion (the burrow, or molting pouch)
-Often difficult to diagnose in infants because of its atypical appearance
-Common. Infection has nothing to do with cleanliness.
-Caused by a mite called Sarcoptes scabiei
-Acquired by significant close physical contact and through fomites (bedding, clothes)
-Pruritis caused by mite burrowing into the skin to lay eggs
-Most intense time of itching is at night
-Common distribution sites: Wrists, elbows, fingers and toes
-Definitive diagnosis relies on the identification of mites, eggs, eggshell fragments, or fecal pellets:
--Superficial skin samples should be obtained from characteristic lesions by scraping laterally across the skin with a blade
--Specimens can be examined with a light microscope under low power with mineral oil
-More common in young adults than children
-Usually appears scaly, with cracks and fissures between the toes
-Infection with the yeast form of a fungus (Malassezia globosa), part of normal skin flora
-May be contagious
-Excess heat and humidity predispose to infection
-Pink, brown or white lesions with fine scale
-Recurrences common, may take months for pigment changes to return to normal
"ringworm of the scalp"
-Slow-growing fungus in hair follicles
-Kerion: An inflamed, weeping boggy lesion caused by a significant allergic response to the fungus
-Caused by human papillomavirus (HPV)
-Caused by mulloscum contagiosum virus
-Lesions are small, smoother than common warts, and may have a central dimple ("umbilicated")
What are five different causes of diaper rash?
1. Irritant dermatitis
2. Diaper candidiasis
3. Bacterial infection
4. Zinc deficiency
5. Langerhans cell histiocytosis
-Most common diaper rash
-Due to prolonged exposure to moisture, friction and/or digestive enzymes (worse with diarrhea)
-Irregular areas of erythema with skin maceration on convex surfaces of the skin
-Typically spares the intertriginous creases
Erythematous papules that become confluent, bright red plaques surrounded by more erythematous papules (satellite lesions)
Bacterial infection cause of diaper rash:
-Usually in perianal area
-Often caused by Group A Strep (Step pyogenes)
-Potentially serious, leading to cellulitis and even dissemination via bacteremia
-Infant may be irritable
-May see streaks of blood on stools
-Infrequent cause of significant diaper rash
-May result from either nutritional deficiency (acrodermatitis enteropathica) or malabsorption (cystic fibrosis).
Langerhans cell histiocytosis
-Crusty, weepy lesions that may bleed
-Biopsy required for diagnosis
What are primary lesions?
Macule, Patch, Papule, Plaque, Vesicle, Bulla, Pustule, Nodule, Wheal, Telangectasia, Petechiae, Purpura
What are secondary lesions?
Scale, Crust, Fissure, Erosion, Ulcer, Excoriation
Flat, circumscribed discoloration (eg, freckle) Less than or equal to 1 cm.
Larger, flat lesion of color change of the skin. Greater than 1 cm.
Elevated, circumscribed solid lesion (eg, mole). Less than or equal to 1 cm.
Broad, elevated lesion; may represent a confluence of papules. Greater than 1 cm.
Circumscribed, elevated, fluid-containing lesion. Less than 1 cm.
Larger, circumscribed, elevated, fluid-containing lesion. Greater than 1 cm.
Circumscribed collection of leukocytes. Variably sized.
Circumscribed, elevated lesion that involves the dermis and extends into subQ tissue. The majority of a nodules is below the skin.
Elevated lesion characterized by superficial transient edema. May be white to pale red and often appear and disappear over a period of hours.
A dilation of superficial venules, arterioles, or capillaries visible on the skin.
Tiny, red or purple macules caused by capillary hemorrhage under the skin or mucous membrane. Do not blanch with pressure.
Larger, purple lesion caused by bleeding under the skin. May be palpable. Does not blanch with pressure.
Flakes of keratin that can be fine or coarse, loose or adherent
Dried remains of serum, blood, or pus overlying involved skin
Linear, often painful cleavage in the cutaneous surface of the skin.
Slightly depressed lesion in which all or part of the epidermis has been lost. Does not extend into the underlying dermis, so healing occurs without scar formation.
Depressed lesion extending into the dermis or subQ tissue. May lead to scar formation.
Traumatized, superficial loss of the skin caused by scratching or rubbing.
What is on the differential for acute urticaria (hives)?
Papular urticaria. Streptococcal infection, Erythema multiforme, Drug eruption.
What are less likely differential diagnosis for acute urticaria?
Erythema infectiosum (Fifth disease), Erythema migrans, Roseola
-Due to type 1 hypersensitivity
-Affects up to 15 percent of the pop at some point in their lives
-Classic lesion is an intensely pruritic, circumscribed, raised, erythematous wheal, often with central pallor.
--Individual lesions may enlarge and coalesce with other lesions
--Lesions continually change with new lesions occurring as old ones resolve.
--Individual lesions last 12-24 hours
--Due to histamine release from mast cells during allergic inflammation
--Generally rules out diagnoses such as viral exanthema
--If an antihistamine alleviates the sx, this supports a theory of an allergic reaction
--Dog saliva (a more significant allergen than dander)
-Family history of atopic triad (asthma, eczema, and allergies) suggests possibility of allergic reaction
-Common pediatric condition caused by insect bites (may appear after a child has been outside).
-Lesions are pruritic, but smaller than in acute urticaria (3-10 mm), more papular, and may be, recurrent or chronic (tending to last one to two weeks).
-Most commonly associated with the rash of scarlet fever
-Erythematous, fine, sandpaper-like rash accentuated at skin creases.
-Uncommonly causes an urticarial rash, similar in appearance to acute urticaria, but associated systemic symptoms would also be present.
-Acute hypersensitivity syndrome associated with a symmetrical rash that starts as dusky red macules and evolves into sharply demarcated wheals and then into target-like lesions
-Individual lesions stay fixed for 1-3 weeks
-Most commonly caused by herpes simplex infection, but may be associated with medications
-Type 1 hypersensitivity reactions or may result from non-immunologic triggers of mast cell release, such as from opiates or non-steroidal anti-inflammatories
Erythema infectiosum (fifth disease):
-Starts on face with "slapped cheek" appearance followed by a reticular, lacy erythematous rash on trunk and extremities.
-Caused by parvovirus B19
-Lesion associated with early localized Lyme disease
-Starts as red papule at the site of the tick bite and expands to form a large, erythematous, annular patch.
-Viral exanthem that classically follows three to five days of a febrile illness
-Pink, maculopapular rash that starts on the trunk and may spread to the face and extremities
-Caused by human herpes virus-6 (HHV-6)
What is on the differential diagnosis for seborrheic dermatitis (cradle cap)?
Atopic dermatitis (eczema), Candidal rash, Psoriasis
Seborrheic dermatitis (cradle cap):
-Erythematous plaques with fine to thick greasy yellow scale
-Typically seen on the call, but may spread to the ears, neck, and diaper area of infants
-In older patients, often caused by a fungus called malassezia
Eczema (atopic dermatitis):
-May involve posterior scalp
-Positive history of atopic diathesis would support this diagnosis
-May find pruritic, erythematous, scaling plaques on extensor surfaces as evidence of atopic dermatitis on other areas of the body.
-Commonly manifests as a diaper dermatitis peaking between ages seven and ten months
-Area of erythema in the inguinal region, as well as erythematous papules and plaques with satellite lesions
-May or may not be pruritic
-Erythematous with a thick, non-waxy scale and defined borders.
-Look for signs of psoriasis elsewhere on the patient's body
-Family history of psoriasis is present in 40 percent of patients
What is on the differential diagnosis fro acne vulgaris?
Staphylococcal folliculitis and furunculosis, Pseudofolliculitis, Erythema nodosum, Hidradenitis suppurativa
-Reason from greater than 4.5 mill drs visits a year
-85 percent of patients are age 12-24 yrs
-Caused by keratinous material and excess sebum (due to androgens) plugging pilosebaceous glands
-Increased sebum provides growth medium for superinfection with proponiobacterium acnes
-Located on neck, face, chest, upper back and upper arms (areas with greatest number of sebaceous glands)
-Course of disease:
1. Starts as open comedones (blackheads) or closed comedones (whiteheads)
2. Lesions can then become inflamed, which may lead to larger, erythematous lesions called papules or pustules
3. If lesions continue to progress, may lead to nodulo-cystic acne
Staphylococcal folliculitis and furunculosis:
-May look similar to nodular or cystic acne
-Often located below the waist or in the groin area
-Papules (not pustules)
-Often located in the beard area
-Inflammation is adjacent to hair follicles
-Caused by shaved hairs regrowing in surrounding skin, causing irritation and inflammation
-Red, tender, nodular lesions on pretrial surface of the legs
-Etiologies include infections, drugs and inflammatory bowel disease
-Occlusion of the apocrine follicular units
-Often super infected with staph aureus or strep pyogenes
-Pustular lesions, but distribution markedly different from acne:
--Women: Axillae, groin and inframammary regions
--Men: Perineal and perianal areas
-More often seen in adults
-"Early" form seen in adolescents
-Inflammatory papules and micro pustules
-Redness on malaria and nasal surfaces
-Exacerbated by alcohol, spicy food, temperature extremes, stress
-Located around the mouth, nose or eyes
-Variant of rosacea
-Commonly seen in adolescents
-Erythema, scaling and papules or pustules
-Historically related to topical corticosteroid use
-Common delayed type IV hypersensitivity reaction
-Onset within 24-72 hours from start of contact
-Can occur despite prior tolerance to exposure
-Resolves within days to weeks of avoidance
--Topical antibiotics such as the common generic "triple antibiotic ointment" or bacitracin
--Plants in the toxicodendrons (or Rhus) genus (poison ivy, oak, and sumac)
-Chronic contact dermatitis may appear as erythematous, scaly plaque.
-Acute contact dermatitis is erythematous, vesicular, edematous and is extremely pruritic
-"Weepy" with honey-colored crusts
-Below the nares is most common site (because of rubbing and colonization), but can be anywhere on the body.
-Most common bacteria: Staph aureus and Strep pyogenes (Group A strep)
--Topical antibiotics (eg, mupirocin)
--Due to widespread emergence of methicillin-resistant staph aureus (MRSA), watch for invasive complications such as abscess formation
--Complications merit systemic antibiotics
What is on the differential for tinea corporis (ringworm)?
Nummular eczema, Psoriasis, Pityriasis alba, Pityriasis rosea
Tinea corporis (ringworm)
-Hx of contact with animals
--Annular, well-circumscribed, scaly plaque with a raised border and the center becoming brown or hypopigmented
--Gradually enlarges and may coalesce with surrounding lesions
--Mildly pruritic or asymptomatic
-Dx usually clinical, but a KOH wet-mount examination of skin scrapings can confirm the diagnosis.
--Obtain scrapings with the edges of a glass slide or a 15 blade and examine them under low power with the microscope light dimmed.
--Observe classic branches and rod-shaped septated hyphae
-Coin-shaped lesions commonly found on legs and buttocks
-Annular configuration and scaly appearance
-Erythematous papules and plaques with a thick silver scale.
-May have annular configuration
-Chronic disease (unlike tinea)
-Patches of hypo pigmentation on the face, neck, upper trunk, and proximal extremities
-Lesions range from 0.5 to 5 cm in diameter and have well defined, irregular borders and fine scale
-Associated with sun exposure
-Can be mistaken for tinea versicolor
-Scaly papules and plaques in "Christmas tree" distribution on back and trunk, following the lines of skin cleavage.
-Lesions may also be found in the upper thighs and groin area
-Initial lesion, called the "herald patch" is usually the largest scaly plaque with a raised border