A 42-year-old man complains of skin lesions on his legs for the last 6 weeks. He has become concerned because they are enlarging rapidly, are painful, and have started to drain pus. He has not had similar symptoms before. The patient has no trauma to the area, fevers, or night sweats. He takes analgesics for chronic low back pain and is on a lactose-free diet due to diarrhea. The patient tries to be compliant with his diet but still has crampy abdominal pain and frequent bowel movements, occasionally at night. He does not use intravenous drugs.
His vital signs are normal. Skin examination is shown in the photograph.

Laboratory analysis shows an elevated C-reactive protein and erythrocyte sedimentation rate. X-ray of both legs reveals no bony erosions or soft-tissue gas.
Which of the following is the most likely diagnosis?

Question

A 42-year-old man complains of skin lesions on his legs for the last 6 weeks.  He has become concerned because they are enlarging rapidly, are painful, and have started to drain pus.  He has not had similar symptoms before.  The patient has no trauma to the area, fevers, or night sweats.  He takes analgesics for chronic low back pain and is on a lactose-free diet due to diarrhea.  The patient tries to be compliant with his diet but still has crampy abdominal pain and frequent bowel movements, occasionally at night.  He does not use intravenous drugs.
His vital signs are normal.  Skin examination is shown in the photograph.

Laboratory analysis shows an elevated C-reactive protein and erythrocyte sedimentation rate.  X-ray of both legs reveals no bony erosions or soft-tissue gas.
Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec193a_9786_483c_853d_7be34eee4101_MD0002_00 This patient's presentation is consistent with pyoderma gangrenosum (PG), a rare neutrophilic, ulcerative skin disease. PG initially starts as a tender papule, pustule, or vesicle. Over time, it expands outward and begins to disintegrate centrally with noted purulence and a necrotic base. This leads to central ulceration with ragged and violaceous outer borders. PG can have a single or multiple lesions and appears most frequently on the trunk or lower extremities. In about 30% of cases, preceding trauma can induce or aggravate PG, a process known as pathergy. More than 50% of PG patients have an associated underlying systemic disorder such as inflammatory bowel disease (IBD), arthropathies (eg, rheumatoid arthritis), or hematologic conditions (eg, acute myeloid leukemia). PG can present before or at the time of diagnosis of these underlying diseases. This patient's combination of chronic back pain, crampy abdominal pain, frequent diarrhea, and elevated C-reactive protein and erythrocyte sedimentation rate strongly suggests spondyloarthropathy with IBD. PG is often a diagnosis of exclusion. Skin biopsy findings are nonspecific in PG but are usually required to exclude other similarly presenting conditions (eg, venous ulcers, panniculitis, cutaneous cancers). Mild and localized PG (few superficial lesions) should be treated with a high-potency topical corticosteroid or topical tacrolimus. Systemic glucocorticoids with or without cyclosporine are usually indicated for patients with extensive PG or failure to respond to local interventions. (Choice A) Erythema nodosum presents as tender, erythematous nodules/plaques due to a delayed hypersensitivity to antigens in drugs or other conditions (eg, streptococcal infection). Although these lesions can be associated with IBD, they do not ulcerate and typically resolve after 2-8 weeks without scarring. Erythema nodosum (Choice B) Leukocytoclastic vasculitis is a hypersensitivity vasculitis and usually presents with palpable purpura and systemic symptoms (eg, fever, arthralgias, diarrhea). (Choice C) Scrofuloderma (seen in both Mycobacterium tuberculosis and M bovis infections) usually presents as firm, painless, subcutaneous, and red-brown nodules. The skin lesions are typically due to direct extension of a deep structure (commonly lymph node) infection into the overlying skin. They can eventually ulcerate and form draining sinus tracts with purulent and watery material. However, they are less common with current effective tuberculosis therapies. (Choice D) Necrobiosis lipoidica presents with asymptomatic skin lesions that appear as indurated, yellowish plaques with central atrophy and are most often located on the shins. It is an inflammatory skin disorder found most commonly in diabetics. Necrobiosis lipoidica Educational objective: Pyoderma gangrenosum is a rapidly progressing, painful ulcer with a purulent base and violaceous borders. More than 50% of patients have associated systemic disease (eg, inflammatory bowel disease). Treatment usually requires local or systemic corticosteroids. __________ References: Etiology and management of pyoderma gangrenosum: a comprehensive review. (http://www.ncbi.nlm.nih.gov/pubmed/22356259) Pyoderma gangrenosum. A comparison of typical and atypical forms with an emphasis on time to remission. Case review of 86 patients from 2 institutions. (http://www.ncbi.nlm.nih.gov/pubmed/10670408) Skin ulcers misdiagnosed as pyoderma gangrenosum. (http://www.ncbi.nlm.nih.gov/pubmed/12409543)

A 42-Year-Old Man Complains of Skin Lesions on His Legs