anticonvulsant hypersensitivity syndrome
Pronunciation: AN-tie-kon-VUL-sant HY-per-sen-si-TIV-ih-tee SIN-drohm
Also written as: AHS — anticonvulsant hypersensitivity syndrome
Severe, potentially life-threatening allergic reaction to antiepileptic medications involving skin, liver, and other organs.
Full Definition
Anticonvulsant hypersensitivity syndrome (AHS) is a serious adverse drug reaction that typically occurs within the first 2-8 weeks of starting certain antiepileptic drugs, particularly aromatic anticonvulsants like phenytoin, carbamazepine, and phenobarbital. The syndrome presents with fever, skin rash (often progressing to Stevens-Johnson syndrome), lymphadenopathy, and multi-organ involvement including hepatitis, nephritis, and hematologic abnormalities. Genetic predisposition exists, particularly HLA-B*1502 allele in patients of Asian ancestry taking carbamazepine. Early recognition and immediate discontinuation of the offending drug is crucial, as the syndrome can progress to life-threatening complications.
Usage
Usage note: Also known as DRESS syndrome. Emphasize genetic testing considerations in at-risk populations before prescribing aromatic anticonvulsants.
In Context
- "The patient developed AHS three weeks after initiating phenytoin, requiring immediate drug discontinuation and steroid therapy." — Emergency department consultation
- "Genetic testing for HLA-B*1502 was recommended before starting carbamazepine in this patient of Chinese ancestry." — Pharmacogenomic consultation note