subcorneal pustular dermatosis (Sneddon-Wilkinson disease)

Etiology

• may represent a form of pustular psoriasis
• no etiologic pathogen has been identified

Epidemiology

• rare
• most commonly affects women > 40 years of age

Pathology

• benign but chronic disorder
• direct & indirect immunofluorescence staining of skin biopsy is commonly negative
• a subgroup may have IgA deposition against desmocollin 1
• accumulation of neutrophils in the subcorneal layer suggests the presence of chemoattractants in the uppermost epidermis

Clinical manifestations

• chronic relapsing sterile pustular eruption
• primary lesions are flaccid pustules, several millimeters in diameter, on normal or mildly erythematous skin
• classic lesion is a '1/2-1/2' blister, in which purulent fluid accumulates in the lower 1/2 of the blister
• pustules may be grouped or isolated; they tend to coalesce
• pustules are superficial & rupture easily, resulting in a superficial crust
• mild hyperpigmentation often remains after pustular lesions have resolved
• most commonly affected areas include the axillae, groin, neck, & submammary region
• proximal flexural aspects of the extremities may be affected
• palmar, plantar, face & mucous membrane involvement is unusual

Laboratory

• serum protein electrophoresis: monoclonal gammopathy in 40%
• skin culture for bacteria, fungi
• skin scraping, KOH mount

Differential diagnosis

• dermatitis herpetiformis
• pemphigus foliaceus
• dermatophytosis
• pemphigus, IgA
• pustular psoriasis
• eosinophilic pustular folliculitis
• impetigo

Management

• dapsone is treatment of choice
• acitretin has been used successfully
• PUVA may be useful
• systemic or topical glucocorticoids generally not effective
• empiric antibiotics if cellulitis suspected

More general terms

• skin disease (dermatologic disorder, dermatopathy, dermatosis)