Question

A 24 year old male comes to his physician after noticing multiple "bumps" on his hands and legs. There is a burning sensation in the lesions, but they do not itch. Eight days prior, the patient was found to have cold agglutinins and was started on erythromycin to treat Mycoplasma pneumoniae. The patient denies any recent travel or sick contacts, but does work with immigrants at his job as an immigration officer. Physical examination reveals numerous vesiculobullous lesions symmetrically on the palms of the hands and on the extensor surfaces of the arms and lower legs. A photograph of this patient's lesions is seen here. Which of the following is the most likely diagnosis in this patient?

A. Erythema multiforme
B. Smallpox
C. Fixed drug eruption
D. Stevens-Johnson syndrome
E. Rocky Mountain spotted fever

Answer 1

Erythema multiforme is the most likely diagnosis for the patient's symmetric vesiculobullous lesions on the palms and extremities, likely related to erythromycin treatment for Mycoplasma pneumoniae.

Step-by-step explanation:

The most likely diagnosis for a 24 year old male with symmetric vesiculobullous lesions on the palms of the hands and on the extensor surfaces of the arms and lower legs is Erythema multiforme (A). Considering his recent treatment with erythromycin for Mycoplasma pneumoniae, his symptoms could be a reaction to the medication. Another important aspect to rule out would be any potential infectious diseases, considering his work with immigrants. However, given the distribution of the lesions and the recent antibiotic use, a fixed drug eruption (C) is less likely to present symmetrically, Stevens-Johnson syndrome (D) is typically associated with severe mucosal involvement and a more extensive rash, Rocky Mountain spotted fever (E) would feature a petechial rash beginning at the hands and wrists, spreading to the trunk, which does not completely match the presented case. Smallpox (B) is unlikely due to the eradication of the disease and lack of recent travel or contact history.