Associated Pyoderma Gangrenosum, Erythema Elevatum Diutinum, and Chronic Recurrent Annular Dermatosis: The Neutrophilic Disease Spectrum

Neutrophilic dermatoses (ND) refer to a group of skin diseases characterized histologically by a cutaneous infiltrate of mature polymorphonuclear cells without an identifiable cause. Previously described as autonomous, these clinically distinct entities are included in the spectrum of neutrophilic disease due to the existence of overlapping forms, as described in our observation. Erythema elevatum diutinum (EED) is a rare dermatosis characterized by reddish-violaceous to browning papulonodular and plaques and belongs to the spectrum of cutaneous leukocytoclastic vasculitis. Chronic recurrent annular neutrophilic dermatosis (CRAND) is an exceptional neutrophilic dermatosis characterized by chronic annular lesions and the absence of generalized signs or hematological abnormalities. Histological features are similar to those seen in Sweet's syndrome. A 55-year-old woman with a history of pyoderma gangrenosum (PG) presented successively with two rare forms of ND, namely, EED and CRAND. There were no clinical or paraclinical arguments for any underlying systemic disease. Treatment with azathioprine 100 mg/day and topical steroids led to a total regression of lesions after a nine-month follow-up. Our observation is important because it reports two rare entities, CRAND and EED. Their occurrence in a single patient with a history of PG illustrates the concept of "neutrophilic disease" reported in the 1990s.