0071643192.pdf

DERMATOLOGY

■ Eczematous: Resemble contact dermatitis but are more extensive, erythe-

matous, or papular eruptions that can become vesicular eg, topical med-

ication with prior sensitization

■ Vasculitic: Urticarial papules or palpable purpura that can ulcerate due to

immune-complex mediated vasculitis; purpuric lesions may rarely be from

bone marrow suppression or platelet destruction

■ Photosensitive:

■ Phototoxic: Sulfonamides, sulfonylureas, thiazide diuretics, tetracyclines

taken in adequate amounts cause sunburn appearance on sun-exposed

areas of skin; nonimmunologic

■ Photoallergic: Antigen formation from drug causing delayed response of

2 weeks or longer after exposure to drug and sunlight; eczematous and

intensely puritic (eg, chlorpromazine, promethazine, chlordiazepoxide)

■ Fixed drug reactions: Appear and reappear in the same sites after repeat

exposure to the same drug; sharply marginated oval or round lesions (eg,

tetracyclines, sulfonamides, NSAIDs)

TINEA

ETIOLOGY

■ Dermatophytoses, superficial fungal infections of the outer keratin layer

of skin, hair, nails, are caused by fungal species from one of three genera

(Trichophyton, Microsporum, andEpidermophyton); more common in

warm, moist environments; not markedly contagious except for tinea

capitus

DIAGNOSIS

■ Usually can be diagnosed clinically

■ Confirmation may be achieved with microscopic identification of branch-

ing hyphae after KOH prep or Wood’s lamp evaluation showing yellow-

green fluorescence; most useful for tinea capitis.

TREATMENT

■ Topical antifungal agents are usually effective. Systemic therapy (griseofulvin,

itraconazole, or terbinafine) required for infections of the hair and nails and

for recalcitrant disease.

■ Tinea barbae: Beard and neck

■ Tinea capitis: Scalp

■ Tinea corporis: Ringwormlike configuration on the body with sharply

marginated, annular lesions with raised or vesicular margins and central

clearing

■ Tinea cruris: Groin and pubic region

■ Tinea pedis: Athlete’s foot

■ Kerion: Dermatophytic infection of the scalp that appears as an

indurated, boggy plaque with overlying pustules; treated the same as

tinea capitis (oral antifungals) with the addition of prednisone 1 mg/kg/

day for 1–2 weeks (see Figure 17.3)

■ Tinea unguium (onychomycosis): Nails

■ Tinea versicolor: Superficial infection caused by Pityrosporum ovale;

causes scaling patches of various colors, pink, tan white usually on the

chest and trunk; treated with selenium sulfide shampoo, imidazole

creams, or oral ketaconazole