Pyoderma Gangrenosum

Etiology of pyoderma gangrenosum is unknown, but it can be associated with various systemic illnesses, including inflammatory bowel disease Overview of Inflammatory Bowel Disease Inflammatory bowel disease (IBD), which includes Crohn disease and ulcerative colitis, is a relapsing and remitting condition characterized by chronic inflammation at various sites in the gastrointestinal... read more , rheumatoid arthritis Rheumatoid Arthritis (RA) Rheumatoid arthritis is a chronic systemic autoimmune disease that primarily involves the joints. Rheumatoid arthritis causes damage mediated by cytokines, chemokines, and metalloproteases.... read more , cancers, and hematologic disorders (eg, monoclonal gammopathy of undetermined significance Monoclonal Gammopathy of Undetermined Significance (MGUS) Monoclonal gammopathy of undetermined significance (MGUS) is the production of M-protein by noncancerous plasma cells in the absence of other manifestations typical of multiple myeloma. (See... read more , myelodysplastic syndrome Myelodysplastic Syndrome (MDS) The myelodysplastic syndrome (MDS) is group of clonal hematopoietic stem cell disorders typified by peripheral cytopenia, dysplastic hematopoietic progenitors, a hypercellular or hypocellular... read more , polycythemia vera Polycythemia Vera Polycythemia vera is a chronic myeloproliferative neoplasm characterized by an increase in morphologically normal red cells (its hallmark), but also white cells and platelets. Ten to 15% of... read more ). It is thought to be mediated by an abnormal immune response. Most patients are age 25 to 55. It can manifest in various subtypes.

Pathophysiology of pyoderma gangrenosum is poorly understood but may involve problems with neutrophil chemotaxis. Interleukin-8 is overexpressed in lesions. Ulcerations of pyoderma gangrenosum occur after trauma or injury to the skin in about 30% of patients; this process is termed pathergy.

Most often, pyoderma gangrenosum begins as an inflamed erythematous papule, pustule, or nodule. The lesion, which may resemble a furuncle or an arthropod bite at this stage, ulcerates and expands rapidly, developing a swollen necrotic base and a raised dusky to violaceous border. An undermined border (ie, loss of underlying support tissue at the border) is common, if not pathognomonic. Systemic symptoms such as fever and malaise are common. The ulcers can coalesce to form larger ulcers, often with cribriform or sieve-like scarring.

Symptoms and signs can vary with the subtype.

Diagnosis of pyoderma gangrenosum is clinical and is a diagnosis of exclusion after other causes of ulceration have been ruled out. Expansion of ulceration after surgical debridement strongly suggests pyoderma gangrenosum. Biopsies of lesions are not often diagnostic but may be supportive; 40% of biopsies from a leading edge show vasculitis with neutrophils and fibrin in superficial vessels.

Patients who have bullous (atypical) pyoderma gangrenosum should be monitored with periodic clinical assessment and complete blood count for development of a hematologic disorder.

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

For more severe manifestations, prednisone 60 to 80 mg orally once a day is a common first-line therapy. TNF-alpha inhibitors (eg, infliximab, adalimumab, etanercept) are effective, particularly in patients who have inflammatory bowel disease Overview of Inflammatory Bowel Disease Inflammatory bowel disease (IBD), which includes Crohn disease and ulcerative colitis, is a relapsing and remitting condition characterized by chronic inflammation at various sites in the gastrointestinal... read more . Cyclosporine 3 mg/kg orally once a day is also quite effective, particularly in rapidly progressive disease. Dapsone, azathioprine, cyclophosphamide, methotrexate, clofazimine, thalidomide, and mycophenolate mofetil have also been used successfully. Antimicrobials such as minocycline have also been used for vegetative (superficial) pyoderma gangrenosum.

Surgical treatments are avoided because of the risk of wound extension (1 Treatment reference Pyoderma gangrenosum is a chronic, neutrophilic, progressive skin necrosis of unknown etiology often associated with systemic illness and sometimes skin injury. Diagnosis is clinical. Treatment... read more ).