What is responsible for her tender rash?

A 40-year-old female developed a rash on one hand that was tender to touch. She had started on doxycycline the day prior to treat an upper respiratory infection. There is no history of trauma or exposure history.

What is responsible for her tender rash?

A. Insect bite reaction
B. Contact dermatitis
C. Cellulitis
D. Fixed drug eruption
E. Underlying arthritis

(Answer and discussion on next page)

Answer: Fixed drug eruption   

This patient had developed a fixed drug eruption to the doxycycline. Changing the antibiotic was sufficient for resolution. Other diagnoses are reasonable, but did not have the history to support them. The erythema was not bright enough for cellulitis and the rash did not center over the joint.