The etiology of pyoderma gangrenosum is unknown; it may be associated with various systemic diseases, including inflammatory bowel disease, rheumatoid arthritis, cancers, and hematologic diseases.

It is considered an abnormal and exacerbated immune response.

Most patients are 25 to 55 years old. 

The pathophysiology of pyoderma gangrenosum is poorly understood, but may involve problems with neutrophil chemotaxis. Interleukin-8 is overexpressed in the lesions. Ulcerations can appear after trauma or skin injury in about 30% of patients, such as after a surgical procedure.

Signs and symptoms

Most often, it begins as an inflammatory erythematous papule, pustule, or nodule.

In cases after surgery, it may present as a postoperative dehiscence, difficult to close, with a differential diagnosis of cutaneous infection.

Systemic symptoms such as fever and malaise are common. Ulcerations may coalesce to form large ulcers.

• Clinical evaluation

The diagnosis of pyoderma gangrenosum is clinical and is a diagnosis of exclusion after other causes of ulceration have been ruled out. Expansion of the ulceration after surgical debridement strongly suggests pyoderma gangrenosum. Skin biopsies are not diagnostic, but should be taken at the edge of the lesions, and in 40% of cases, vasculitis with neutrophils and fibrin is present in superficial vessels.

Patients with bullous (atypical) pyoderma gangrenosum should be monitored with periodic clinical evaluation and complete blood count to determine if hematologic disease develops.

• Wound care

• Corticosteroids

• Tumor necrosis factor (TNF)-alpha inhibitors

• Sometimes other immunosuppressants or anti-inflammatories

• Avoid surgical debridement due to possible disease progression

Wound healing can be promoted with moisture-retaining occlusive dressings for less exudative plaques and absorbent dressings for highly exudative plaques. Biological dressings and other specialized dressings may be necessary in refractory cases. Wet-to-dry dressings should be avoided. Topical treatment with high-potency corticosteroids or tacrolimus may help superficial and early lesions.

For more severe manifestations, prednisone, 60 to 80 mg orally once daily is a common first-line therapy. TNF-alpha inhibitors (e.g., infliximab, adalimumab, etanercept) are effective, particularly in patients with inflammatory bowel disease. Cyclosporine, 3 mg/kg orally once daily is also very effective, particularly in rapidly progressive disease. Dapsone, azathioprine, cyclophosphamide, clofazimine, thalidomide, and mycophenolate mofetil have also been successfully used. Antimicrobial agents such as minocycline have also been used for vegetative (superficial) pyoderma gangrenosum.

Surgical treatments are avoided due to the risk of wound extension (1).

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