What are neutrophilic dermatoses?

Neutrophilic dermatoses are autoinflammatory skin conditions characterised by dense infiltration of inflammatory cells (neutrophils) in the affected tissue. They arise in reaction to some underlying systemic illness. A neutrophilic dermatosis may be seen in isolation or more than one type may occur in the same individual.

Neutrophilic dermatoses often arise at the site of injury such as a needle prick, biopsy or insect bite. This reaction to injury is known as Koebner phenomenon, or isomorphic response. Pathergy refers to papules and pustules appearing at the site of needle stick.

Subcutaneous Sweet disease

Sweet disease caused by vemurafenib

Pyoderma gangrenosum

Neutrophilic dermatoses include:

• Acute febrile neutrophilic dermatosis (Sweet syndrome)
• Histiocytoid neutrophilic dermatitis
• Neutrophilic dermatosis of the dorsal hands
• Pyoderma gangrenosum
• Neutrophilic eccrine hidradenitis
• Erythema elevatum diutinum
• Behcet disease
• Bowel bypass syndrome (bowel-associated dermatitis-arthritis syndrome)
• Neutrophilic urticarial dermatosis
• Palisading neutrophilic granulomatous dermatitis