What underlying health issue can cause erythema nodosum?

Erythema nodosum is an inflammatory condition characterized by painful, raised nodules primarily found on the lower legs. It is often associated with a variety of underlying health issues, and one notable condition that can lead to its development is pregnancy. During pregnancy, hormonal changes and physiological alterations can trigger immune responses, leading to conditions like erythema nodosum.

Several other factors, such as infections (like streptococcal infections), drug reactions, or inflammatory diseases (like sarcoidosis), may also contribute to the occurrence of erythema nodosum. However, in this context, pregnancy stands out as a well-recognized association due to the unique autoimmune and inflammatory changes during this time.

The other health issues listed—diabetes mellitus, hypertension, and asthma—are not commonly associated with the development of erythema nodosum. While they each have their own complications and skin manifestations, they do not typically provoke the specific inflammatory response that results in the formation of erythema nodosum. Thus, pregnancy remains the correct choice as an underlying health issue that can cause this particular skin condition.