Diagnostic challenges in subcorneal pustular dermatosis

Subcorneal pustular dermatosis, also known as Sneddon–Wilkinson disease, is a rare recurrent condition, and its nosology remains a subject of debate. It is often placed within the spectrum of bullous dermatoses and interpreted as a subtype of pemphigus; however, some contemporary studies consider it a neutrophilic dermatosis, and even a potential variant of pustular psoriasis.

Clinically, Sneddon–Wilkinson disease presents with eruptions on normal or erythematous skin in the form of flaccid, superficial, small (2–4 mm) sterile pustules, which are often grouped, forming annular or garland-like patterns. The process is typically symmetrical.

The etiopathogenesis remains incompletely understood, though current evidence indicates that the key pathogenic mechanism is the accumulation of neutrophils beneath the stratum corneum, possibly due to an abnormal neutrophilic response to aberrant chemotactic factors located within the upper epidermal layers.

Diagnosis of Sneddon–Wilkinson disease is challenging, because its clinical presentation closely resembles several other conditions. Another difficulty is in the need to distinguish subcorneal pustular dermatosis from pustular psoriasis. Diagnosis is based on clinical presentation and histopathological examination, where subcorneal neutrophilic accumulation is key.

The issue of treatment for this type of dermatosis remains relevant, with dapsone being the first-line option. In cases of poor response or contraindications, alternative modalities may be used, including systemic glucocorticoids, retinoids, PUVA therapy, and tumor necrosis factor-α (TNF-α) inhibitors.

This article presents a rare clinical case of Sneddon–Wilkinson disease in a 20-year-old pregnant patient in her second trimester, with a year-long disease history, diagnostic difficulties, and challenges in therapeutic management.