THREE TYPESAcute: Acute onset with painful hemorrhagic pustule or painful nodule either de novo or after trauma. There is the phenomenon of pathergy, where a needle prick, insect bite, biopsy, or other minimal trauma can trigger a lesion. Chronic: Slow progression with granulation and hyperkeratosis. Less painful. Bullous: True blisters often hemorrhagic and associated with hematologic disease.
SKIN LESIONSAcute: Superficial hemorrhagic pustule surrounded by erythematous halo; very painful (Fig. 7-1). Breakdown occurs with ulcer formation, whereby ulcer borders are dusky-red or purple, irregular and raised, undermined, and boggy with perforations that drain pus (Fig. 7-2). The base of the ulcer is purulent with hemorrhagic exudate, partially covered by necrotic eschar (Fig. 7-3), with or without granulation tissue. Pustules both at the advancing border and in the ulcer base; a halo of erythema spreads centrifugally at the advancing edge of the ulcer (Fig. 7-3). Chronic: Lesions may slowly progress, grazing over large areas of the body and exhibiting massive granulation within the ulcer from the outset (Fig. 7-4) with crusting and even hyperkeratosis on the margins (Fig. 7-5). Lesions are usually solitary but may be multiple and form clusters that coalesce. Most common sites: Lower extremities (Figs. 7-2 and 7-5) > buttocks > abdomen (Fig. 7-3) > face (Fig. 7-4). Healing of ulcers results in thin atrophic cribriform scars. Bullous: Blisters from the outset, often hemorrhagic, followed by ulceration.
MUCOUS MEMBRANES Rarely, aphthous stomatitis-like lesions; very rarely massive ulceration of oral mucosa and conjunctivae.
Up to 50% of cases occur without associated disease. The remainder of cases are associated with arthritis, large- and small-bowel disease (Crohn disease and ulcerative colitis), diverticulosis (diverticulitis), paraproteinemia and myeloma, leukemia, autoimmune hepatitis, Behçet syndrome (which is also a disease with pathergy).
Clinical findings plus history and course; confirmed by compatible dermatopathology. Differential diagnosis: Ecthyma and ecthyma gangrenosum, atypical mycobacterial infection, clostridial infection, deep mycoses, amebiasis, leishmaniasis, bromoderma, pemphigus vegetans, stasis ulcers, and granulomatous vasculitis.
WITH ASSOCIATED UNDERLYING DISEASE Treat underlying disease.
SYSTEMIC TREATMENT High doses of oral glucocorticoids or IV glucocorticoid pulse therapy (1 to 2 mg/kg) may be required. Cyclosporine can also be considered as a first-line treatment for severe disease. Second-line and adjunctive treatment options include TNF-alpha inhibitors, mycophenolate mofetil, methotrexate, azathioprine, and dapsone.
TOPICAL Local disease can be treated with topical and intralesional steroids.