Subcorneal pustular dermatosis
There is no racial or ethnic predilection, but the disease is more common in women and in those over the age of 40.
Lesions tend to be asymptomatic, but patients may report itching or burning. Although the disorder's presentation may look severe, it is a benign condition.
SPD usually presents as crops of small, flaccid pustulovesicles that coalesce into annular or serpiginous configurations on previously normal skin. The lesions most commonly occur symmetrically on the flexural extremities, as well as the axillae, groin, abdomen, and inframammary skin. The pustules dry up after a few days, leaving scaling and crusts that may resemble impetigo. This is followed by new crops of vesicles or pustules developing at the periphery of older lesions, leaving annular or polycyclic lesions. The lesions resolve without scarring but may leave postinflammatory hyperpigmentation. This cycle may repeat itself a few days or weeks later if the patient is not treated.
The etiology of SPD is unknown. SPD has been described in association with IgA paraproteinemia and IgA myeloma. Associations with , , , rheumatoid arthritis, and systemic lupus erythematosus have also been reported. Additionally, associations with SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, osteitis), thyroid dysfunction, endocrine tumors, and polycythemia vera have been reported.
L13.1 – Subcorneal pustular dermatitis
25147002 – Subcorneal pustular dermatosis
Differential Diagnosis & Pitfalls
- Tinea corporis – Positive potassium hydroxide (KOH) preparation and hyphae on biopsy.
- Bacterial impetigo – Asymmetrical, has bacteria present on Gram stain, and typically responds to antistaphylococcal antibiotics.
- Dermatitis herpetiformis – Favors extensor surfaces; histology shows subepidermal neutrophils.
- Pemphigus foliaceus – Histology shows acantholysis.
- Pustular psoriasis – Histology shows intraepidermal spongiform pustules; can present with systemic symptoms (fever, malaise), which are typically lacking in SPD.
- Necrolytic migratory erythema (associated with glucagonoma syndrome) – Lacks actual pustules, and patients have oral mucous membrane erosions; histology shows necrobiosis of the upper epidermis.
- Acute generalized exanthematous pustulosis – A widespread pustular eruption on a background of erythroderma, often with associated systemic symptoms.
- SPD-type IgA pemphigus – Intraepidermal IgA deposits on immunofluorescence.
- Eosinophilic folliculitis of Ofuji
Drug Reaction Data