PT - JOURNAL ARTICLE AU - Susanna Wang AU - Jennifer Morrical TI - Erythema nodosum as key manifestation of histoplasmosis case AID - 10.1136/bcr-2022-251876 DP - 2022 Nov 01 TA - BMJ Case Reports PG - e251876 VI - 15 IP - 11 4099 - http://casereports.bmj.com/content/15/11/e251876.short 4100 - http://casereports.bmj.com/content/15/11/e251876.full SO - BMJ Case Reports2022 Nov 01; 15 AB - Histoplasmosis is a systemic infection caused by the fungus, Histoplasma capsulatum. Infection of H. capsulatum frequently occurs by inhaling the spores of the fungus, which is found in bat and bird droppings, or soil enriched with their excrement. If not detected and treated, histoplasmosis can develop late, severe complications such as mediastinal fibrosis, or even develop into a disseminated infection. However, histoplasmosis infections are often asymptomatic, making its detection more difficult. Further, only 6% of histoplasmosis cases will present with erythema nodosum, with most cases associated with female patients. This case presents a woman in her 50s with a pertinent history of fibromyalgia and hypothyroidism secondary to Hashimoto’s who initially sought medical care for painful nodules on her legs and was eventually diagnosed with histoplasmosis. This report clearly demonstrates the importance of maintaining a broad differential when working up inflammatory manifestations, such as erythema nodosum.