Which physical exam finding is most indicative of systemic lupus erythematosus in a patient with joint pain and oral ulcers?

The presence of joint pain and oral ulcers in a patient suggests an autoimmune process, and systemic lupus erythematosus (SLE) is one condition that can manifest in this manner. In SLE, specific skin findings hold important diagnostic significance.

The involvement of the extensor surfaces of the hands and arms is particularly indicative of SLE. This pattern is associated with conditions like lupus erythematosus, where erythematous rashes can appear on the extensor surfaces. This distribution aligns with the typical rashes seen in SLE, such as the discoid rash or the characteristic malar rash (butterfly rash) around the face, which, while more classically associated with SLE, can also involve extension surfaces.

Other choices mentioned do not strongly correlate with SLE. For instance, chronic eczematous dermatitis is more associated with allergic reactions and irritations, which are not specific to lupus. Involvement of the nasolabial folds could be indicative of other dermatological conditions and typically does not align with the rashes characteristic of SLE. Lastly, the skin overlying the knuckles can show certain changes, such as in dermatomyositis, but is not specifically indicative of lupus.