Pyoderma Gangrenosum on Both Legs of a 62-Year-Old Woman

Worsening painful ulcers on both legs prompted a 62-year-old woman to seek medical attention. She had a history of rheumatoid arthritis (RA), demonstrated by the markedly deformed interphalangeal joints in her thumbs (A), and scleroderma-polymyositis overlap syndrome.

A 3.8-cm pseudovesicular ulcerated plaque was noted on the right ankle (B); a similar lesion was present on the left ankle. Punch biopsy revealed epidermal necrosis with dense neutrophilic inflammatory infiltrate in the dermis with leukocytoclasis and some fibrin deposition (C, D, and E, from low to high magnification). These findings were consistent with pyoderma gangrenosum.

The necrotizing ulcers of pyoderma gangrenosum can mimic severe bacterial infection as well as Sweet syndrome, collagen-vascular diseases, halogenodermas, malignant neoplasms, factitial ulcerations, brown recluse spider bites, bullous erythema multiforme, and purpura fulminans.^1-6 First identified by Brocq in 1916, this rare skin disorder begins as a papulopustular rash and progresses to an inflamed violaceous ulcer with ragged borders and surrounding induration and erythema.^2-6 Multiple ulcers often develop on the lower extremities.^1-3,5-7 More than 50% of patients with pyoderma gangrenosum have an underlying systemic disease and up to 37% have associated arthritis.^1-3,5,7

Suspect pyoderma gangrenosum in a patient with RA who presents with an ulcerative skin lesion. In one study, RA was the most common condition associated with pyoderma gangrenosum.⁷ In a study of 86 patients who had pyoderma gangrenosum, 14% had RA.³ Certain identifiable factors (including skin fragility, arterial disease, peripheral edema, nutritional status, and venous insufficiency) can predis-pose patients with RA to pyoderma gangrenosum.¹

The exact cause of pyoderma gangrenosum associated with RA is not fully understood. Some theorize that immune complexes or a defective immune system may play a role. The presence of IgM, IgG, IgA, C3, and fibrin on direct immunofluorescence studies suggests that the cause is an immunological reaction to immune complex deposition.⁴ However, pathergy may be a contributing factor. In patients with pathergy, lesions develop in areas of trauma.^2,6 Pathergy occurs in 20% to 30% of patients with pyoderma gangrenosum.^3,6 The proinflammatory cytokine interleukin-8 (IL-8) also may be involved in the pathogenesis. IL-8 is not expressed in normal skin but is overexpressed in certain chronic skin conditions, such as pyoderma gangrenosum.²

Treatment consists of local wound care, analgesics, therapy for secondary bacterial infections, and systemic corticosteroids.^4,5 If corticosteroids are contraindicated or the lesions persist despite this treatment, other agents, such as dapsone, may be used. Severe refractory disease may respond to cyclosporine.⁴ Surgical debridement is not recommended because it may result in further tissue damage and progression of lesions in patients with pathergy.⁶ The ulcers usually heal as an atrophic, cribiform scar.^3,5,6

This patient received oral prednisone (60 mg once a day). The skin lesions rapidly resolved, and the medication was slowly tapered over the next 2 months.

References:

REFERENCES

1. Charles CA, Bialy TL, Falabella AF, et al. Poor prognosis of arthritis-associated pyoderma gangrenosum. Arch Dermatol. 2004;140:861-864.

2. Trent JT, Kirsner RS. Diagnosing pyoderma gangrenosum. Adv Skin Wound Care. 2001;14:151-153.

3. Bennett ML, Jackson JM, Jorizzo JL, et al. Pyoderma gangrenosum. A comparison of typical and atypical forms with an emphasis on time to remission. Case review of 86 patients from 2 institutions. Medicine (Baltimore). 2000;79:37-46.

4. Bennett CR, Brage ME, Mass DP. Pyoderma gangrenosum mimicking postoperative infection in the extremities. A report of two cases. J Bone Joint Surg Am 1999;81:1023-1018.

5. Ma G, Jones G, MacKay G. Pyoderma gangrenosum: a great marauder. Ann Plast Surg. 2002;48:546-552.

6. Tay YK, Friednash M, Aeling JL. Acute pyoderma gangrenosum does not require surgical therapy. Arch Fam Med. 1998;7:377-380.

7. von den Driesch P. Pyoderma gangrenosum: a report of 44 cases with follow-up. Br J Dermatol. 1997;137:1000-1005.