Papulosquamous Lesions

Papulosquamous is a term used for skin lesions that are papular and present in the superficial skin layer (the squamous layer). Papulosquamous rashes are defined as exanthems that have palpable epidermal changes with scale. The diagnoses within the papulosquamous categories are quite broad and must be considered systematically on the basis of history and physical examination, and only occasionally with a biopsy. The distribution of the lesions is a key characteristic that helps with a correct diagnosis.

Differential Diagnosis

• Allergic and irritant contact reactions and drug-induced rashes are included in the papulosquamous diseases

• Psoriasis
  –Affects 2% of the U.S. population
  –May acutely present as guttate (drop-like), round plaques with minimal scale
  –More common is the variant called psoriasis vulgaris: Presents as thick plaques of silvery adherent scale on an erythematous base on the extensor joints
• Seborrheic dermatitis
  –An inflammatory “dandruff” that manifests as light scale on a greasy and/or erythematous background around the hairline, upper lip, nasolabial creases, chin, external ears, eyebrow areas, scalp
  –Due to overgrowth of Pityrosporum ovale
• Pityriasis rosea
  –A common exanthem that is self-limited; the etiology is unclear
  –Presents with initial “herald patch,” with subsequent scaly pink papules/plaques over the trunk in a “Christmas tree” distribution
  –May be very itchy and is often confused with guttate psoriasis
• Atopic dermatitis
  –Common among children with a history of asthma, hay fever, or seasonal allergies
  –Manifests as itchy eczematous plaques on the antecubital and popliteal fossae; often becomes secondarily lichenified (i.e., thickened with chronic rubbing changes)
  –60% of patients have initial symptoms before 1 year of age
  –The disease often lasts 15–20 years

• Fungal infections of the skin caused by dermatophytes often present as itchy, scaly papulosquamous rashes that can mimic nummular eczema
• Nummular eczema
  –An idiopathic disease that affects many patients mostly in the winter months
• Lichen planus
  –Present with flat topped, polygonal, and purplish papules that may have white streaks or “Wickham's striae”

Workup and Diagnosis

• Perform a focused history and physical examination
  –Evaluate for family history of psoriasis or other skin disease
  –Look for fingernail pitting, subungual debris, distal separation of the nail plate from the nail bed (called onycholysis), and “oil spots” (extravasated proteins under the nail) that are characteristic of psoriasis; always consider psoriasis if the scale is markedly silver and very thick/adherent to the skin
• Seborrhea of the face and scalp is far more common than psoriasis of these areas, and it has a much thinner and lighter scale
• Pityriasis rosea presents in healthy young adults after a viral prodrome; observe carefully for the larger, thicker herald patch to confirm the diagnosis; patients can often point the first patch out to you, because it appeared several days before the more diffuse eruption
• Consider atopic dermatitis in a young patient with allergic rhinitis or asthma and a very itchy, chronic, or subacute rash that is often symmetric on the flexural skin
• A KOH preparation and examination by light microscope can quickly establish the diagnosis of a dermatophyte infection
• Patch testing to potential allergens and review of a patient's chemical exposure can help rule in allergic contact or irritant dermatitis, respectively

Treatment

• Psoriasis can be effectively controlled
  –Topical calcipotriene is a nonsteroidal, long-term agent used to control the cutaneous disease
  –Topical steroids, tar, and anthralin preparations; intralesional steroids; salicylic acid and ultraviolet light therapy; methotrexate; acitretin; cyclosporin; and newer biologic therapies such as alefacept and etanercept are used as well
  –Avoid using systemic steroids whenever possible, because a severe flare is common upon their completion
• Pityriasis rosea is managed symptomatically with oral antihistamines, topical steroids, topical antipruritics (e.g., sarna, calamine), and, in severe cases, with oral steroids, erythromycin or phototherapy
• Atopic dermatitis
  –Must be approached as a disease of skin barrier function; it is crucial to repair that function with the use of gentle cleansers, emollient creams/oils, topical steroid ointments

Book Source Details

• Book Title: In a Page: Signs and Symptoms
• Author(s): Scott Kahan, Ellen G. Smith
• Year of Publication: 2004
• Copyright Details: In a Page: Signs and Symptoms, Copyright © 2004 Lippincott Williams & Wilkins.

Other Book Chapters Related to Rash

Read excerpts from these other book chapters related to Rash:

Copyright Details: In a Page: Signs and Symptoms, Copyright © 2008 Williams & Wilkins.

More About Causes of Rash

• Back to symptom: Rash: Introduction (review 1085 causes)
• Next Book Extract About Rash: Vesicular & Bullous Lesions (In a Page: Signs and Symptoms)
• All Book Extracts: All Online Book Extracts for Rash

More About This Book: Title: In a Page: Signs and Symptoms Authors: Scott Kahan, Ellen G. Smith Publisher: Lippincott Williams & Wilkins Copyright: 2004 ISBN: 1-4051-0368-X