Fixed drug eruption
Fixed drug eruption is a distinctive cutaneous drug reaction that presents acutely as erythematous, edematous plaques with a grayish center or frank bullae and recurs at the exact same skin site with every re-exposure to the culprit drug, leaving dark postinflammatory pigmentation behind. A small number of localized lesions are managed with topical triamcinolone acetonide 0.1% ointment twice daily for 7 to 10 days and drug withdrawal, while generalized or generalized bullous disease with systemic symptoms may warrant prednisone 0.5 to 1 mg/kg orally once daily for 3 to 5 days.
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What this article covers
- Overview
Definition: fixed drug eruption is a distinctive cutaneous drug reaction characterized acutely by erythematous and edematous plaques with a grayish center or frank bullae, and chronically by dark postinflammatory pigmentation.
- Epidemiology
Occurs within the broader drug eruption population: adverse cutaneous drug reactions overall affect 2 to 3 percent of hospitalized patients, and about 1 in 1000 hospitalized patients has a serious…
- Risk factors
Prior exposure to the culprit drug: because the eruption is a re-exposure phenomenon at a fixed cutaneous site, any patient with a prior episode is at risk with subsequent exposure to the same drug.
- Pathophysiology
T cell-mediated, site-resident mechanism: the mechanism is not fully understood, but T cells that reside in the skin at the affected site are thought to drive the reaction, producing interferon gamma upon re-exposure to the drug.
- Clinical features
Acute lesion morphology: an erythematous and edematous plaque with a grayish center, or a frank bulla, most often on the lips or tongue, genitalia, face, or acral skin.
- Differential diagnosis
Stevens-Johnson syndrome/toxic epidermal necrolysis: distinguished from generalized bullous fixed drug eruption by more prominent and severe mucosal involvement and a more severe systemic illness…
- Diagnosis
Clinical diagnosis anchored by the site-recurrence pattern: the diagnosis is made from the combination of a characteristic acute plaque or bulla, dark postinflammatory pigmentation, and a history of…
- Management
First, identify and withdraw the culprit drug, since discontinuation of the offending agent is the essential step in every case and prevents recurrence at the fixed site.
- Complications
Recurrence with re-exposure: the eruption reliably recurs, often more rapidly and sometimes more extensively, at the same site with any subsequent exposure to the causative drug.
- Prognosis
Favorable with drug withdrawal: fixed drug eruption, including the generalized bullous variant, has a favorable clinical course, with generalized bullous fixed drug eruption resolving rapidly within…
- Prevention
Avoid re-exposure to the identified culprit drug: the single most effective preventive measure, since the eruption is defined by its reproducible recurrence with re-exposure to the causative agent.
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