Rosh Internal Medicine Boost Practice Exam

In a patient presenting with rash and joint pain, which skin finding is most suggestive of systemic lupus erythematosus?

1. Chronic eczematous dermatitis

2. Involvement of the extensor surfaces of the hands and arms

3. Involvement of the nasolabial folds

4. Involvement of the skin overlying the knuckles

The correct answer is: Involvement of the extensor surfaces of the hands and arms

In the context of systemic lupus erythematosus (SLE), the most suggestive skin finding is the involvement of the extensor surfaces of the hands and arms. This is characteristic because SLE typically presents with a variety of skin manifestations, but the specific finding of lesions on the extensor surfaces is a hallmark of the disease. These lesions include a type of photosensitive rash that can appear as erythematous papules or plaques. The extensor surface involvement is important to recognize because it helps clinicians differentiate SLE from other dermatoses. In contrast, other skin conditions associated with joint pain may have different distribution patterns. For instance, conditions like psoriatic arthritis typically affect the extensor surfaces as well, but the specific rash of SLE is more closely associated with the disease process, which includes immune-mediated damage leading to inflammation and rash. Other options suggest various skin findings that are less characteristic for SLE. Chronic eczematous dermatitis, for example, is more indicative of atopic dermatitis and presents differently. Involvement of the nasolabial folds is also a finding more common in conditions such as seborrheic dermatitis, while involvement of the skin overlying the knuckles might hint at conditions like dermatom