A 60-year-old gentleman presented to a clinic with a large ulceration over his left tibia. The wound was friable, erythematous, and purulent, with necrotic involvement of the tibial tendon sheath. He reports that the lesion started 15 years ago and worsened after surgical debridement 10 years ago. High-dose prednisone helped in the past, but other medications have been of no help. Recently, the patient developed intense pain with occasional fevers, chills, and night sweats. He has type 2 diabetes mellitus, but denies any history of bowel difficulties, hepatitis, or arthralgias. What is your diagnosis?
a) Antiphospholipid antibody syndromeb) Cryoglobulinemia
c) Brown recluse spider bite
d) Pyoderma gangrenosum
e) Necrobiosis lipoidica diabeticorum
This man has pyoderma gangrenosum (PG), characterized by a boggy, expanding, painful ulceration which most commonly occurs on the leg. His acute symptoms result from osteomyelitis, which is one of the unfortunate complications of the disease.
PG usually presents with an inflammatory papule or pustule that quickly progresses to a painful ulcer with a violaceous undermined border and a purulent base. PG is an often-considered diagnosis, but it is actually an uncommon condition with an incidence rate of 3 to 10 patients per 1 million patients annually.
This patient’s hepatitis panel, cryoglobulins, antinuclear antibody (ANA), anti-neutrophil cytoplasmic autoantibodies (ANCA), rheumatoid factor (RF), and coagulation profile showed no significant abnormalities. Previous pathology showed a mixed inflammatory picture, but no vasculitis or malignancy; thus, the patient was diagnosed with PG.
The etiology of PG is still undetermined, although it is linked to inflammatory conditions in 50% of cases, with inflammatory bowel disease being the most common, followed by myleoproliferative disorders and arthritis.1 The literature describes “pathergy” in this disease where it is common to develop new lesions at areas of trauma or with surgical intervention, including debridement if not accompanied by immune-suppressant medications. Systemic steroids for 6 weeks can successfully treat flares, but long-standing disease should be managed by cyclosporine, infliximab, azathioprine, and other immunosuppressives.2
Antiphospholipid antibody syndrome (AAS) can cause skin ulcerations, but a negative ANA and no thrombosis on the patient’s pathology ruled that out. Cryoglobulinemia causes purpuric lesions, so the pathology would have revealed a vasculitic pattern. Brown recluse spider bites can acutely cause skin necrosis, but do not progressively worsen ulceration over years. Necrobiosis lipoidica diabeticorum usually — but not always — occurs in diabetics. The condition sometimes causes ulcerations, but in contrast to this patient, it usually has yellowing and thinning of the skin and can be confirmed on biopsy.
1. Ruocco E, Sangiuliano S, Gravina AG, et al. Pyoderma gangrenosum: an updated review. J Eur Acad Dermatol Venereol. 2009 Sep; 23(9):1008-17. http://onlinelibrary.wiley.com/doi/10.1111/j.1468-3083.2009.03199.x/abstract.
2. Callen JP, Jackson JM. Pyoderma gangrenosum: an update. Rheum Dis Clin North Am. 2007 Nov;33(4):787-802, vi. http://www.rheumatic.theclinics.com/article/S0889-857X(07)00052-X/abstract.
About the Author
Daniel Stulberg, MD, is a Professor of Family and Community Medicine at the University of New Mexico. After completing his training at the University of Michigan, he worked in private practice in rural Arizona before moving into full-time teaching. Stulberg has published multiple articles and presented at many national conferences regarding skin care and treatment. He continues to practice the full spectrum of family medicine with an emphasis on dermatology and procedures.
Stulberg was assisted in writing this article by Miguel Gomez, a fourth year medical student at the University of New Mexico.