Scaling Rash

Differential Overview

❑ Eczema

❑ Atopic dermatitis

❑ Seborrheic dermatitis

❑ Tinea versicolor

❑ Pityriasis rosea

❑ Psoriasis

❑ Contact dermatitis

❑ Tinea corporis

❑ Tinea manuum

❑ Stasis dermatitis

❑ Drugs

❑ Lichen planus

❑ Secondary syphilis

❑ Reiter

❑ Bowen disease

❑ Cutaneous T-cell lymphoma

Clinical Findings

Eczema  Red, poorly defined patches appear on the neck and flexor surfaces and thicken with excoriations caused by excessive scratching. Coinlike (num-mular) lesions are common on the lower legs.

Atopic dermatitis  Pruritus/scratching lead to eczematous lesions. A personal or family history of atopy (asthma, allergic rhinitis) is elicited. An extra fold of skin below the lower eyelid is a common finding.

Seborrheic dermatitis  Pink-red scaly patches with an indistinct outline develop in the scalp, eyebrows, nasolabial crease, behind the ears, in the ear canal, over the sternum, and in intertriginous areas. New-onset severe seborrheic dermatitis may be the first sign of HIV infection.

Tinea versicolor  A finely scaled macular eruption appears over the trunk. Hypopigmented macules may occur on dark skin; hyperpigmented macules occur on light skin.

Pityriasis rosea  Salmon-pink oval lesions have their long axis following the cleavage lines of the skin. Lesions have a collarette of fine scale around the perimeter. They are distributed on the trunk and proximal extremities, sparing the palms (involved in secondary syphilis). There is usually a herald patch, which is the initial and largest lesion.

Psoriasis  Pink-red sharply demarcated plaques have a silvery micaceous scale. They occur on the elbows, knees, scalp, and gluteal crease. There is often nail dystrophy with pitting, onycholysis, and yellow discoloration. Guttate psoriasis—a widespread eruption of small, scaling lesions—may be brought on by streptococcal infection, lithium, beta-blockers, rapid steroid taper, or acute HIV infection. It spares the face, palms, and soles.

Contact dermatitis  Well-demarcated lesions develop in areas of thin, exposed skin. Lesions are in a localized distribution, reflecting the contact exposure. Common precipitants include poison ivy, nickel jewelry, formaldehyde (in clothing and nail polish), fragrances, perservatives, topical antibiotic cream, rubber, and tanning chemicals. Latex exposure can cause type I hypersensitivity reactions in addition to allergic contact dermatitis.

Tinea corporis  Red annular lesions have an active scaling border with central clearing. The inner thigh is a typical location.

Tinea manuum  One hand is gray-red with scaling within the palmar creases, associated with scaling and nail dystrophy on both feet.

Stasis dermatitis  The lower extremities are edematous, red, and scaling. A brownish discoloration develops due to hemosiderin; it occurs especially over the medial ankle.

Drugs  Pityriasis rosea-like lesions may be seen with beta-blockers, captopril, clonidine, gold, griseofulvin, isotretinoin, metronidazole, and penicillin. Lichenoid eruptions can be produced by gold, antimalarials, thiazides, quinidine, phenothiazines, sulfonylureas, furosemide, methyldopa, griseofulvin, beta-blockers, and captopril.

Lichen planus  Lesions appear as violet-colored, polygonal, and flat-topped papules, traversed by a network of thin gray-white lines (Wickham striae). They occur in the flexor aspects of the wrists, ankles, and glans penis. The oral mucosa also has lacy white plaques or erosions. The plaques are only scaly on the legs.

Secondary syphilis  Scattered red-brown papules with thin scale often involve the palms or soles. Associated findings that assist diagnosis are systemic symptoms such as fever, malaise, and lymphadenopathy; recent (4 to 8 weeks previously) chancre; annular plaques on the face; alopecia; or broad-based and moist condyloma lata.

Reiter  Psoriasiform lesions occur in a patient with arthritis, urethritis, and/or uveitis.

Bowen disease  A single, well-demarcated plaque with variable scale develops in a patient with a known history of arsenic exposure, or exposure manifest as palmar hyperkeratosis.

Cutaneous T-cell lymphoma  Retiform (net-like) psoriatic lesions appear without the typical distribution, with an increase in palpability, and do not respond to topical steroids. The earliest lesions are macular, scaly, and red, admixed with yellow (poikiloderma).

Book Source Details

• Book Title: Field Guide to Bedside Diagnosis
• Author(s): David S. Smith
• Year of Publication: 2007
• Copyright Details: Field Guide to Bedside Diagnosis, Copyright © 2007 Lippincott Williams & Wilkins.

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Copyright Details: Field Guide to Bedside Diagnosis, Copyright © 2008 Williams & Wilkins.

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More About This Book: Title: Field Guide to Bedside Diagnosis Authors: David S. Smith Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 0-78178-165-5

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