Fixed drug eruption caused by metronidazole

Co-existing sensitivity to metronidazole and isothiazolinone

“…Metronidazole, a widely used synthetic antiprotozoal and antibacterial agent, is generally well tolerated. There have, however, been isolated reports on cutaneous adverse reactions to the drug, among them immediate allergic reactions and urticaria, 1,2 acute generalized exanthematous pustulosis, 3,4 and serum sickness 5 as well as several cases of fixed drug eruption 6–13 …”

“…There have, however, been isolated reports on cutaneous adverse reactions to the drug, among them immediate allergic reactions and urticaria, 1,2 acute generalized exanthematous pustulosis, 3,4 and serum sickness 5 as well as several cases of fixed drug eruption. [6][7][8][9][10][11][12][13] Topical use of metronidazole gel has been reported to cause burning, stinging, redness, irritation, itching, or worsening of rosacea. In clinical trials, individual events occurred in less than 10% of patients treated (http:// www.metrogel.com/index.cfm).…”

Allergic contact dermatitis to topical metronidazole – 3 cases

“…Metronidazole used as a topical agent is generally well tolerated, and contact dermatitis to topically applied metronidazole is rare and only two cases have been published previously (1, 2). There have been isolated reports of immediate allergic reactions and urticaria (3–5), fixed drug eruptions (6–13) and acute generalized exanthematous pustulosis (14) due to topical metronidazole. Vincenzi et al (1) investigated their patient for possible cross reactions to other imidazole derivatives, but did not find any, in accordance with our finding in case III.…”

Hypersensitivity reactions to metronidazole

“…However, the majority are cases of fixed exanthemas linked to medication. In some cases positive epicutaneous tests have been recorded with metronidazole at different concentrations 8,14,15 .…”