Dermatology - ​Fixed Drug Reaction

Dermatology - ​Fixed Drug  Reaction 

An unfavorable cutaneous reaction to an ingested medicine is known as a fixed drug eruption, and it is typified by the development of a single (or sometimes several) erythematous patch or plaque. Tetracyclines, sulfa medications, metronidazole, nystatin, salicylates, NSAIDs, phenylbutazone, phenacetin, barbiturates, oral contraceptives, quinine, quinidine, phenolphthalein, and food coloring (yellow) are the most often implicated substances. Within hours of consumption, if the patient is reexposed to the offending drug, the FDE reoccurs at the same (fixed) skin spot.

In a previously sensitized person, lesions might develop 30 minutes to 8 hours after drug administration and can be itchy, unpleasant, or burning. Lesions go away in a few days to a few weeks after the medication is stopped.
Damage
Hours after ingesting the offending medicine, a well-defined patch of erythema turns into a dusky red to violaceous macule or plaque. Lesions are usually solitary and can grow to be rather large, although they can also be many and dispersed randomly.
Lesions may progress to painful bullae and eventually erosions. Postinflammatory hyperpigmentation with a dark brown to violet tint may appear after recovery. Although the genital area is most commonly affected, other sites such as the perioral, periorbital, conjunctival, and oropharyngeal regions may also be affected.


Once the offending medication is stopped, the lesions must heal for the diagnosis to be considered clinical.

Give up the problematic substance. Apply antibacterial ointment to erosions. Oral prednisone at a dose of 1 mg/kg body weight decreased over a period of 2 weeks is recommended for mucosal lesions that are extensive, generalized, and extremely painful.