Dermatology Flashcards
Folliculitis
Infection of the hair folicle usually by S. aureus
Typically located on the buttocks or lower extremities, can also occur on the scalp
Treatment options
Antibacterial soap every other day for several weeks
Topical clindamycin BID until resolved
Impetigo
Skin infection of the top layer of the epidermis usually caused by S. aureus
Non-bullous- vesicles or pustules that open to form honey colored crusts
Bullous- bullae (large blisters) containing clear fluid rupture leaving behind denuded varnish like crust skin with blister remnant
Treatment
MRSA increasingly common
Clean lesions daily
Topical mupirocin BID-TID
Consider oral antibiotic for extensive involvement
Erythromycin, Augmentin, Keflex in pre MRSA time
Clindamycin or Trimethoprim-Sulfamethoxazole if MRSA is concern
Pyoderma
Skin infection extending from epidermis into the dermis usually caused by group A streptococci
Begins as pustule/vesicle that ruptures forming a crust; when crust removed, note ulcer into dermal layer
Regional lymphadenopathy
Oral antibiotic (PCN or clindamycin)
Cellulitis
Deep, locally diffuse infection of the skin with systemic manifestations, usually caused by strep or staph, varies by age and site of infection
May reflect a more deep-seated, non visible infection
Clinical findings
+/- fever
+/- ill appearing
Inflammation at site (erythema, edema, heat, tenderness)
Consider diagnostics if hospitalizing or neonate (< 2 mts), immunocompromised, unvaccinated individuals
Treatment
Outpatient-oral antibiotics (erythromycin, cephalexin, trimethoprim-sulfamethoxazole)
Inpatient - broad spectrum IV abx (rocephin etc.) while waiting for cultures
In immunocompromised blood cultures needed to make sure they aren’t septic
Contact Dermatitis
Allergic - type IV delayed hypersensitivity; requires prior exposure
Toxicodendron (Rhus) Dermatitis
Nickel allergic dermatitis
Irritant- exposure to substances that cause skin inflammation
Irritant diaper dermatitis
Tinea Capitus
Fungal infection of the scalp
3 types:
Alopecia- one or more oval patches of partial or complete alopecia (partial means there is less hair but it is broken)
Seborrheic- patchy or diffuse whitish to grayscale; alopecia subtle
Inflammatory- inflammatory response to fungus; papules, pustules, kerion ( enlarged inflammatory lesions in response to fungus, if you push on it it is fluctuant, will resolve when you treat the fungus)
Treatment:
- Griseofulvin 20 mg/kg/day PO of microsize prep or 15 mg/kg/day of ultramicrosize prep x 6-8 weeks (dose increases d/t resistance)
- Antifungal shampoo (ketoconazole) twice weekly to decrease shedding of spores
- For severe inflammation (for example for kerion), may consider an oral steroid
- f/u in 1-2 mts
Tinea Corporis
Fungal infection of the skin
Presents with annular lesion with raised border and central clearing
In lighter skin lesion will appear erythematous
In darker skin lesion may appear hyperpigmented
Treatment
Topical antifungal x 2 weeks (OTC, -azole)
Multiple or large lesions may consider oral Griseofulvin (but will need 8 weeks of treatment)
Tinea Versicolor
Fungal infection of the trunk, neck, and proximal extremities in adolescents and adults, rare in children
Overgrowth of M. furfur (normal fungus that grows on skin)
Lesions are scaly macules (flat) that are hyper or hypopigmented, none to minimal pruritus
Treatment
If small area affected- topical antifungal agents
If widespread area (more common)
Selenium sulfide shampoo or lotion- apply to affected area 10 min daily for 7 days, then 8-12 hrs once a month for 3 months
Ketoconazole shampoo- apply to affected area 5 min daily for 1-3 days, then 8-12 hrs once a month for 3 mts
Recurrence is very common
Repigmentation may take months
Pityriasis rosea
Cause is unknown
Commonly occurs in children and adolescents
May have URI prodrome
Begins with single, oval, erythematous/hyperpigmented scaly lesion called a herald patch, days to weeks before rest of rash develops
Then oval plaques with scale in christmas tree or fir tree pattern orienting along skin cleavage
Treatment
No treatment required, self limiting, resolves after 4-8 weeks
May recur
Mild pruritus can be treated with oral antihistamine
Sunlight may help
Seborrheic Dermatitis
Infantile
Cradle cap- yellowish greasy scales to the scalp (may also see on face and flexural area (under neck or behind ear)
Treat by removing scales with mineral oil and brush; may opt to use antiseborrheic shampoo (selsun blue)
Adult (adolescents)
Scaling of the scalp, erythematous scaling patches behind ears, nasolabial folds
For scalp- use antiseborrheic shampoo (can also use on nasolabial fold or ears)
For inflammation to skin- topical steroid
Warts
Verrucae vulgaris (common wart)- typical to dorsal of hand, but may occur anywhere
Verrucae plana (flat wart)- flesh colored to pink-brown, flat topped papules to face, neck, arms, legs; occurs in crops
Verrucae plantaris (plantar warts)- symptomatic wart to weight bearing part of foot
Treatment options
Keratolytic acid therapy
- Salicylic acid available OTC- apply and cover with tape daily (for common and plantar)
- Consider topical retin-A for flat warts
Cryotherapy
Immunotherapy
Duct tape
Self limiting
Molloscum contagiosum
Poxvirus infection resulting in virally induced tumors of the skin
Discrete, skin colored, erythematous, or translucent papules; may note umbilication on top of lesion
Usually appear in clusters and can autoinoculate
**Treatment **
No treatment
Tretinoin topically
Duct tape
Cantharidin - blister beetle excretion - causes it to blister and come off
Cryotherapy
Pediculosis capitis (lice)
Small, six legged wingless insect
Lay eggs called nits which adheres to hair shaft
Can cause erythema/hyperpigmentation at hairline and lymphadenopathy
Treatment- removal of nits; OTC meds; clean bedding, clothes, stuffed animals on high heat settings
Scabies
Infestation with human parasitic mite that burrows under the skin and lays eggs
Incubation as long as 3 weeks
Pruritic rash, particularly to interdigital spaces, wrists, ankles, axillae, groin, palms, soles
May form papular burrows that progress to vesicles or pustules
Treat with 5% permethrin cream- apple to neck down and leave on 8-14 hrs, then rinse, reapply 1 wk later; treat close contacts/ household (not pregnant women or young infants)
You are seeing a 5 year old with a rash to his nose and
upper lip. His mother states that it started with a bump just below his left nostril and spread. The bumps had fluid in them and ruptured forming a crust. You note honey- colored, crusted lesions to the childs upper lip extending into both nostrils. What treatment recommendations do you have?
non bullous Impetigo
- Clean lesions daily
- Topical mupirocin BID-TID
- Consider oral antibiotic for extensive involvement- erythromycin, augmentin, keflex (not MRSA)
or clindamycin or Trimethoprim-Sulfamethoxazole (bactrim) if MRSA is concern
