A patient on phenytoin develops a severe cutaneous adverse reaction with >30% BSA epidermal detachment, mucosal involvement, and systemic features. Which HLA allele has the strongest association with this drug-reaction in South and Southeast Asian populations?

• A HLA-B*58:01 — associated with allopurinol-induced SJS/TEN
• B HLA-A*31:01 — associated with carbamazepine-induced DRESS/SJS
• C HLA-B*15:02 — associated with carbamazepine-induced SJS/TEN in Han Chinese and Asians ✓
• D HLA-B*57:01 — associated with abacavir hypersensitivity

Explanation

The HLA-B*15:02 allele has a strong pharmacogenomic association with carbamazepine (and to a lesser extent, phenytoin and oxcarbazepine)-induced Stevens-Johnson syndrome/TEN in Han Chinese, Thai, and other Southeast Asian populations. This allele is found in 4-8% of Han Chinese but <1% of Europeans. Pre-prescription HLA-B*15:02 screening is now mandatory in Taiwan and recommended in high-risk Asian populations before starting carbamazepine. HLA-B*58:01 is for allopurinol, HLA-B*57:01 for abacavir, HLA-A*31:01 for carbamazepine-DRESS in Europeans.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.