Clinical Approach to Regional Dermatoses

Dermatitis of the Hands and Feet

• An approach to the classification of hand dermatitis is presented in Fig. 13.1 , and the differential diagnosis of foot dermatitis is summarized in Table 13.1 .

  
  Table 13.1

  Differential diagnosis of foot dermatitis.

  Allergic contact dermatitis

  Location of the dermatitis on the dorsal surface versus plantar surface (especially weight-bearing areas) of the feet can reflect an allergen in the top portion or sole of the shoe, respectively Common shoe allergens include dichromate (used to tan leather), adhesive components (e.g. formaldehyde resins, colophony), rubber accelerators, and dyes; allergens implicated in foot dermatitis also include topical antibiotics (e.g. bacitracin) Often associated with atopy and/or hyperhidrosis Lesions extend more proximally in sock/stocking dermatitis, where the most common allergen is azo dyes

  Dyshidrotic eczema

  Pruritic, deep-seated vesicles (often pinhead-sized) on the palms/soles and sides of the fingers/toes Referred to as “pompholyx” when larger vesicles/bullae are present Frequently associated with atopy or contact dermatitis (allergic and irritant)

  Juvenile plantar dermatosis

  “Glazed” erythema, scale and fissuring on the balls of the feet and plantar aspect of the toes Usually occurs in prepubertal children Associated with atopic dermatitis, sweaty feet, and occlusive footwear

  Tinea pedis (athlete’s foot)

  Dermatophyte infections of the plantar skin are usually accompanied by involvement of the interdigital spaces (e.g. maceration) A “moccasin” distribution of diffuse scaling/erythema and a vesicular inflammatory variant favoring the medial foot can also occur Lesions on the lateral and dorsal aspects of the feet tend to have an annular configuration Often associated with tinea unguium

  Psoriasis

  Usually well-demarcated areas of erythema, adherent scale, and often fissuring Psoriasiform plaques elsewhere (e.g. dorsal hands/feet, elbows/knees, scalp) and nail involvement (e.g. pitting, oil spots)

  Pustulosis of the palms and soles

  “Sterile” pustules admixed with yellow-brown macules favoring the instep Often not associated with plaque psoriasis elsewhere Keratoderma blennorrhagicum occurs in the setting or reactive arthritis

  Keratolysis exfoliativa (recurrent focal palmar and plantar peeling)

  Circinate pattern of superficial desquamation (collarettes) on the palms and/or soles Worsens in warm weather and is associated with low-grade irritation/friction

  Keratoderma climactericum

  Mechanically induced hyperkeratosis and fissuring on the heels and weight-bearing areas of the soles Typically occurs in women >45 years of age Predisposing factors include obesity and a cold, dry climate

  Other

  Atopic dermatitis Irritant contact dermatitis (e.g. related to occlusive footwear) Crusted scabies Pityriasis rubra pilaris Inherited palmoplantar keratoderma (diffuse or focal) Acquired keratoderma, e.g. associated with hypothyroidism

  Table 13.2

  Symmetrical drug-related intertriginous and flexural exanthema (SDRIFE): clinical criteria.

  This entity is also referred to as drug-induced intertrigo, flexural drug eruption, and baboon syndrome. The latter term is also used for a form of systemic contact dermatitis.

  Adapted from Häusermann P, Harr TH, Bircher AJ. Baboon syndrome resulting from systemic drugs: Is there strife between SDRIFE and allergic contact dermatitis syndrome? Contact Dermatitis 2004;51:297–310.

  Exposure to a systemically administered drug ∗ , occurring with either the initial or a repeated dose (excluding contact allergens) Sharply demarcated erythema of the gluteal/perianal area and/or V-shaped erythema of the inguinal/genital area Involvement of at least one other intertriginous site/flexural fold Symmetric involvement in affected areas Absence of systemic symptoms and signs

  ^∗ Not a chemotherapeutic agent, so distinct from toxic erythema of chemotherapy.

• Because the hands and feet have a thicker stratum corneum than other areas of the body, percutaneous absorption of topical medications is decreased.

• High-potency topical CS or the use of occlusion may be needed to effectively treat inflammatory dermatoses in these sites.