Hand and Foot Rashes

Hand and foot rashes do not all look alike: Look for the subtle clues discussed below and obtain a detailed exposure and health history to narrow the differential. Be sure to evaluate the full extent of the skin rash before finalizing your differential diagnosis. Dyshidrotic and irritant eczema are by far the most common etiologies of hand and foot rashes.

Differential Diagnosis

• Dyshidrotic eczema (pompholyx)
  –Very common idiopathic skin disease
  –Affects one or both hands and/or feet in the thenar eminence, palms and/or soles, and sides of fingers and toes
  –Causes itching, scaling, and erythema, and minute vesicles and painful fissures
  –Usually chronic and intermittent, and often exquisitely pruritic

• Irritant or allergic hand eczema
  –Very common
  –Difficult to distinguish from dyshidrosis because both are vesicular and very itchy
  –Flares occur during work/hobbies, with improvement on vacation when away from the irritant or allergen
• Tinea manus (hand) and tinea pedis (foot)
  –Presents as itchy, diffuse, light scale, and/or maceration; prominent on palmar, plantar (moccasin distribution), and interdigital surfaces
  –Erythema is rarely present
  –Often “two hands and one foot” or “two feet and one hand” are affected
• Scabies
  –Presents as short (a few millimeters), linear burrows and vesicles on the hands and feet (web spaces), belt region, and/or intertriginous spaces
  –Intensely pruritic, especially at night
  –Often many members of the household unit affected
  –Definitive diagnosis made by visualizing the scabies mite in a skin scraping

• Psoriasis
  –Often affects the hands and/or feet
  –Well-demarcated, erythematous plaques
  with adherent scale, or can present as a focal or diffuse pustular eruption
  –Look for associated nail dystrophy or other skin involvement

• Pityriasis rubra pilaris
  –Well-demarcated bright salmon or red plaques on the palms or soles

• Keratoderma
  –Focal or diffuse thickening of the skin of the palms or soles

Workup and Diagnosis

• History and physical examination
  –Note chronic exposure to chemicals or potential irritants at work or in hobbies
  –Any family history of psoriasis or allergy/atopy
  –Look closely for the presence of small, clear “water blisters” under the skin that may indicate pompholyx
  –Examine nails for evidence of coexisting onychomycosis (very common in cases of tinea pedis and manus, and a nidus for frequent reinfection), “oil spots,” or nail pitting (may suggest psoriasis)
  –Examine joints for arthritis (psoriasis/Reiter's), eyes (Reiter's), and genitalia (psoriasis/Reiter's)

• KOH preparation from scale scraped from the palms, soles, or between the toes to determine presence of branching hyphae of tinea or scabies mites
• Culture any intact pustules
• Consider performing a patch test to rule out allergic contact dermatitis
• A punch biopsy may be helpful to distinguish psoriasis or PRP from the other common eczematous diseases of the hands and feet
• Fungal culture of nail clipping if onycholysis (nail thickening) present
• Dermatology referral is often indicated in resistant cases

Treatment

• Pompholyx, psoriasis, and most noninfectious hand eczemas are treated with topical high potency steroid ointments (e.g., temovate, diprolene) for short periods
• Irritant eczema: Bland heavy emollients (e.g., petroleum jelly, mineral oil, various cream formulations with a dimethicone base) will rehydrate the skin to prevent recurrence of irritant or other types of dermatitis; avoid wet-work, irritants, and harsh soaps
• Tinea manum and pedis
  –Topical antifungal preparations or a short course of oral fluconazole or terbinafine (2 weeks)
  –If onychomycosis is present (confirmed by nail clipping and PAS stain or culture), treat with oral antifungals for 6–12 weeks to prevent recurrence

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.

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

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• Back to symptom: Rash: Introduction (review 1085 causes)
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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