Localized granulomatous pyoderma gangrenosum

Introduction

PG is a rare, destructive, inflammatory skin disease in which a painful nodule or pustule breaks down to form a progressive enlarging ulcer with a raised, tender, undermined bluish border. Other uncommon presentation are superficial granulomatous pyoderma, pyostomatitis vegetans and atypical bullous PG. Lesions may be solitary or multiple and present either in absence of any apparent underlying disorder or in association with systemic disease such as ulcerative colitis crohn′s disease, polyarthritis gammopathy and other conditions.[1] We report a relatively rare localized form of granulomatous PG.

Case Report

A 21-year-old female presented with painful, crusted plaques on her right arm and left thigh of 4 months duration. The lesions had started as a single, painful, red, nodule that gradually increased in size and ulcerated with history of hemorrhagic discharge. Similar lesions appeared over adjacent skin and her left thigh in next 4 months. There was no history of preceding trauma, fever, joint pain, abdorminal pain, altered bower habits, respiratory symptoms and weight loss. There was no personal or family history of diabetes mellitus. Her general physical and systemic examinations were within normal limits. Cutaneous examination revealed three, 1.5cmx2.0cm, erythematous, plaques with hemorrhagic crusting in the center on right arm [Figure - 1]. Thick rough scaling was seen on surface of two of the plaques at the periphery. A single red, tender nodule with pustule formation on top was present in the vicinity of the plaques on the right arm. Similar plaque was present over left thigh. She had received systemic antibiotics without any improvement. Pathergy test was negative (no pustular lesion appeared at the site of venepuncture). Clinical differential diagnoses of pyoderma gangrenosum and granulomatous skin diseases such as deep fungal infection, lupus vulgaris and sarcoidosis were considered.

Her haemogram, stool examination, urinalysis, fasting and post prandial blood sugar levels, renal and liver function tests, and chest x-ray were normal. Scalpel biopsy from a plaque as well as the nodule on the right arm revealed hyperkeratotic, acanthotic and ulcerated epidermis. The dermis showed dense mixed inflammatory reaction consisting of neutrophilis, plasma cells, lymphocytes and foreign body type giant cells. Occasional ill-defined granulomas were also seen. No fungus, bacterial colonies on Gram′s staining, and AFB were seen. Histopathological features were consistent with the diagnosis of granulomatous type of pyoderma gangrenosum (PG).

The patient was given tablet dapsone 100mg OD and twice daily application of clobetasol propionate cream. New lesions stopped appearing an d there was considerable improvement in the existing lesions within 3 weeks of this treatment. However, the patient developed features of hepatitis and anemia in the form of marked anorexia, weakness, pallor and jaundice. Her LFT deteriorated (serum bilirubin-2.9mg/dl, SGOT-353iu/ml, SGPT-256iu/ml). Hb. fell from 13.5gm% to 6.2gm% at the same time. There was no leucopenia or reticulocytosis. Serology for Hbs Ag and HCV was negative. Dapsone was stopped and therapy was changed to intralesional injection of triamcinolone 10mg/ml fortnightly. Her jaundice disappeared and LFT became normal over next 4-weeks. The lesions of PG healed with four intralesional injections of triamcinolone 10mg/ml given fortnightly. There has been no recurrence in the last 3 months.

Discussion

Wilson and Winkelmann described in 1988, a localized, vegetative form of PG with verrucous and ulcerative lesions and more granulomatous histology having umber of plasma cells, and eosinophils in 25 patients. They designated it as superficial granulomatous pyoderma.[2] It was originally described as malignant pyoderma but is now considered to be a variant of PG.[3] Pathergy (pustular lesions appearing at the site of minor trauma) is seen in only 20% of cases of PG. There are no diagnostic/pathognomonic laboratory findings. Histopathology is also not diagnostic. Prominent neutrophilic infiltrate in the absence of infection and response to sulpha drugs puts PG in the group of etiologically ill understood neutrophilic dermatoses such as Sweet′s syndrome, subcorneal pustular dermatosis, and Behcet′s syndrome. PG may occur as a disease confined to skin in 40-50% of cases ("idiopathic" PG). But it may also be associated with inflammatory large and small bowel disease, arthritis, paraproteinemia, myeloma, leukemia, chronic active hepatitis, and Behcet′s syndrome.[1]

Treatment of PG involves treating underlying disease, if any is found. Systemic glucocorticoids are the most effective treatment. High doses of oral corticosteroids (100-200mg prednisolone) O.D. may be required initially. Pulse therapy with suprapharmacologic doses with methylprednisolone (1g/d for 5-days IV) or 100mg dexamethasone in 5% dextrose on 3 consecutive days most effectively halts the progression of the disease and is now the first line treatment in many institutions.1,4 Continued suppression of inflammatory process may require regular pulses at 2 weekly interval initially followed by a 4 weekly schedule once the lesions have healed and there is no evidence of reactivation. The pulses are continued for 3-6 months after complete remission is achieved.[5] Dapsone, sulphapyridine, and sulfasalazine are also very effective drugs. Dramatic responses have been reported with clofazimine. PG has been reported to respond to minocycline, colchicine, heparin, IV vancomycin and mezlocillin. Thalidomide is extremely useful for PG associated with Behcet′s syndrome.[1]

This patient was initially treated with dapsone and potent topical corticosteroid, clobetasone propionate because of the low cost of dapsone and to avoid side effects of systemic corticosteroids in view of her limited disease. However, she developed serious toxicity of dapsone in the form of hepatitis and anemia that are known but uncommon side effects of this drug. She eventually recovered completely from these side effects on stoppage of the drug and was successfully treated with fortnightly intralesional injections of triamcinolone.