Dermatology Q43

Answer & Critique

Correct Answer: B

Educational Objective: Evaluate erythema nodosum with chest radiography.

Key Point

A chest radiograph is recommended in the evaluation of erythema nodosum to assess for the presence of lymphoma, sarcoidosis, tuberculosis, and fungal infection such as coccidioidomycosis.

This patient needs a chest radiograph to complete the evaluation of her erythema nodosum (EN). EN is the most common form of panniculitis, or inflammation of the fat, with most inflammation concentrated on the intralobular septae. Because the inflammation is deep under the skin, the clinical manifestation seen on the surface is often tender, ill-defined erythema with some substance on palpation, which may fade from an active inflammatory red-pink to dull brown. Most commonly, EN occurs bilaterally and symmetrically on the anterior shins; however, it may also appear in any fatty area. Although lesions will often come and go, most resolve over 4 to 6 weeks. EN is a nonspecific reaction pattern occurring in response to some systemic process. EN can be idiopathic, but the most common associations are streptococcal infection, hormones (including oral contraceptives, hormone replacement therapy, or pregnancy), inflammatory bowel disease, sarcoidosis, lymphoma, and medication reactions. The diagnosis of EN can be clinically based on the acute onset of tender nodules on the bilateral shins typically in a young woman. Biopsy is not necessary in typical lesions.

Most authorities recommend a chest radiograph in the evaluation of EN to assess for the presence of lymphoma, sarcoidosis, tuberculosis, and fungal infection such as coccidioidomycosis.

In the absence of gastrointestinal symptoms, a colonoscopy for inflammatory bowel disease is unlikely to reveal a causative diagnosis. Patients with disseminated gonococcal infection and bacteremia manifest vesiculopustular or hemorrhagic macular skin lesions, not tender subcutaneous nodules as seen in this patient.

Patients with disseminated gonococcal infection present with dusky pustules or purpura, fever, chills, and polyarthralgia. Knees, elbows, and distal joints are typical sites of involvement. Subcutaneous nodules are not features of this infection

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