Palisaded neutrophilic and granulomatous dermatitis (PNGD) is an extremely rare inflammatory cutaneous reaction seen in the setting of connective tissue disease or rheumatoid arthritis. It is almost never seen independently from an underlying systemic illness.

Although the exact etiology is unknown, PNGD is likely a reactive process with histological patterns ranging from early neutrophilic inflammation and leukocytoclastic vasculitis to collagen degeneration, granuloma formulation, and associated fibrosis.

PNGD is seen in patients of all ages, though reports of affected children are rare. Women are affected more than men in a 3:1 ratio, which likely reflects the demographics of common underlying autoimmune diseases. Systemic lupus erythematosus and rheumatoid arthritis are the most common associations, although inflammatory bowel disease and systemic vasculitides have also been reported. PNGD has also been rarely reported in association with myelodysplastic syndrome and other lymphoproliferative conditions. It may precede the malignancy diagnosis by up to 5 years, or it may be present at the time of diagnosis.

PNGD presents as symmetrically distributed, skin-colored to erythematous, umbilicated or crusted papules, typically on the elbows and extensor surfaces.

Related topic: paraneoplastic granulomatous eruption