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More than 500 drugs can cause fixed drug eruptions, and the list is growing, according to one expert. The current list of offenders needs to be updated regularly so that physicians can prescribe other drugs to treat their patients.
Mullana, Ambala, India - Most experienced physicians are able to make a quick diagnosis of a fixed drug eruption based on the information gathered from the history as well as the clinical symptoms of the patient.
The familiar list of common drug offenders is long, and, usually, the offending drug can be quickly found by the astute dermatologist. According to one expert in the field, however, this list of common offenders is growing, and the current knowledge of drugs that cause fixed drug eruptions is incomplete and must be updated.
"A fixed drug eruption is a distinct variant of drug-induced dermatoses with characteristic recurrences at the same site of skin or mucous membrane. A number of drugs have been implicated in the causation of fixed drug eruptions. The problem is that the list of commonly known offending drugs keeps on changing from time to time because of the availability of other, better drugs coming out on the market," says Sanjeev Gupta, M.D., D.N.B., M.N.A.M.S., of the MM Institute of Medical Sciences and Research.
In an attempt to update the list of common offenders, Dr. Gupta recently conducted a study including 108 patients who were clinically diagnosed with fixed drug eruptions.
The study was constructed to examine the clinical patterns of fixed drug eruptions and to possibly discover new and previously unreported offending drugs by the use of patch tests and oral provocation, or both.
Results of the study showed that cotrimoxazole topped the list and was found to be the most common offender.
Other drugs that were found to be the cause of fixed drug eruptions either by patch test or oral provocation include:
In the study, Dr. Gupta reported 62 patients with solitary lesions and 46 patients with multiple lesions. The fixed drug eruptions broke down into 99 nonbullous and nine bullous-type fixed drug eruption lesions.
The most common areas of involvement included the extremities and the mucosal glans of the penis, followed by the trunk, lips, face and oral mucosa.
"In our study, we found that an oral provocation test should always be undertaken in case the patch test turned out to be negative. Fixed drug eruption is the only drug reaction in which oral provocation is ethically admissible," Dr. Gupta tells Dermatology Times.
Dr. Gupta says that an oral provocation was only done in those patients where the patch test was found to be negative to all suspected drugs.
In the study, an oral provocation test was considered positive if there was a reappearance of a lesion at an old site and/or symptoms of itching, burning and erythema were reported at the old site.
"Most of the drugs that we found to cause fixed drug eruption in our study have been observed for the first time and have not been reported in literature so far. Therefore, we believe that there is a need to revise the list of offending drugs that cause fixed drug eruptions," Dr. Gupta says.