in which lesions present in the same location upon repeated intake of the offending drug. The lesions typically present within 30 minutes to 8 hours of administration of the drug. These reactions can be considered allergic or pseudo-allergic, in which case, there is no notable adaptive immune response. CD8+ T cells appear to play a role in the epidermal injury via release of interferons and interactions with other inflammatory cells.
Courtesy Lucas Shapiro and Dr. Igor Chaplik
There are numerous drugs that can precipitate these findings. NSAIDs; antibiotics, such as tetracyclines, sulfonamides; and phenytoin are common offenders. In the case of our patient, naproxen was the offending medication.
The classic presentation of FDE features annular, erythematous to violaceous macules on the skin or mucosa that can be asymptomatic or can produce burning, pain, or pruritus. The most common locations include the trunk and extremities, but the palms, soles, face, scalp, and mucosa can also be impacted. The oral mucosa seems to be the most common mucosal location. Intravenous administration of a drug is associated with more severe symptoms. Systemic symptoms are typically absent, and the eruption may initially be in one location, but may appear elsewhere upon repeated exposure to the offending medication.
Dr. Donna Bilu Martin
The differential diagnosis includes arthropod bite reactions, urticaria, and erythema multiforme. Although FDEs are typically a clinical diagnosis, the histopathology will commonly show a vacuolar interface dermatitis. Furthermore, a variety of immune cells can be found, including neutrophilic, eosinophilic, and lymphocytic infiltrate. A combination of two or more histological patterns often favors the diagnosis of FDE.
Steroid creams can be prescribed to decrease the inflammatory reaction and improve symptoms; however, the definitive treatment of this condition is cessation of the offending agent. Postinflammatory hyperpigmentation is a common symptom after resolution of the condition, and it may take months to fade away. Further darkening can be prevented by practicing sun safety measures such as wearing sunblock, covering the affected areas, and avoiding prolonged sun exposure.
This case and the photos were submitted by Lucas Shapiro, BS, of Nova Southeastern University College of Osteopathic Medicine, Fort Lauderdale, Fla., and Igor Chaplik, DO, Aesthetix Dermatology, Fort Lauderdale. The column was edited by Donna Bilu Martin, MD.
Dr. Bilu Martin is a board-certified dermatologist in private practice at Premier Dermatology, MD, in Aventura, Fla. More diagnostic cases are available at mdedge.com/dermatology. To submit a case for possible publication, send an email to dermnews@mdedge.com.
References
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Weyers W, Metze D. Dermatol Pract Concept. 2011 Jan 31;1(1):33-47.