Diagnose on Sight: Recurrent Rash
Case: A 22 year old female presents with a rash on her left arm for several days. She states she has previously had the exact same rash in the exact same location intermittently over the past 2 years. She has no systemic symptoms and has started no new prescription medications, though she has been taking ibuprofen. What is the diagnosis?
[su_spoiler title=”Answer” style=”fancy” icon=”caret”]
Fixed Drug Eruption
Fixed drug eruptions (FDE) are unique drug rashes that recur in the same body sites upon repeated exposure to medications. The rash pictured above is classic for FDE.
Characteristics of the rash1
- Erythematous to violaceous
- Dusky gray centers
- Round to oval-shaped
The rash can occur anywhere on the body. The full list of causative medications is extensive.
Common offending medications include
- Antibiotics (especially trimethoprim-sulfamethoxazole)
- Analgesics (especially nonsteroidal anti-inflammatory drugs)
- Food coloring
- Oral contraceptives
Fixed drug eruption by the numbers1,2
- Minutes to 24 hours: time to rash occurrence after exposure to offending medication
- 7-10 days: time until lesions usually heal
Treatment includes medication avoidance, antihistamines for pruritis, and short courses of oral steroids in severe cases.2
Master Clinician Bedside Pearls
Victoria Brazil, MBBS, MBA, FACEM
Senior Staff Specialist Emergency Medicine, Gold Coast University Hospital
Associate Professor and Director of Simulation, Bond University
My thanks to dermatologist Katrina Spaunhurst, MD for her help with this case.
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