Pyoderma gangrenosum (PG) is an immune-mediated, rare ulcerative disease of the skin. In general it occurs in a genetically susceptible individual. Its incidence ranges from 0.3-1.0/100,000 population. Female are affected more than males.
The cause of PG is not clear but it is attributed that the aberrant chemotaxis of neutrophil to the site of trauma causes development of primary lesion.
The primary lesions are usually small tender papule, pustule, folliculitis or nodule, which breakdown rapidly and progress to a large painful ulcer. The PG ulcer is characterized by violaceous undermined edges, and necrotic floor covered with purulent exudate and associated disproportionate pain. Rarely it may be non-tender. The ulcers last for months to years. The PG has the fluctuating course and it may deveop pathergy and lead to rapid enlargement of the disease.
There is no definite investigations to diagnose PG. To date, diagnosis of PG is by exclusion of other causes of ulcers, associated systemic diseases, correlation of histology with clinical feature or rapid response to high dose corticosteroid.
Treatment with Corticosteroid is satisfactory; cytotoxic drugs are rarely added for treatment of PG. The lesions usually heal with cribriform scar. Recurrence of this disease may occur.
The patient with diagnosis of PG are advised to avoid surgical procedure for the fear of recurrence through pathergy, but when surgery is required, the surgery should be carried out under the supersvion of Dermatologist for atleast 2-3 weeks after surgery to prevent pathergy.