Association of HLA-B*1502 allele and carbamazepine-induced severe adverse cutaneous drug reaction among Asians, a review

Strong association between HLAB*1502 and carbamazepine-induced Steven-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) was demonstrated among Han Chinese in 2004. Studies from Europe showed that the HLA B*1502 is not a universal marker for SJS/TEN, but is ethnicity specific for Asians. Reports across Asia has shown that the prevalence of HLA B*1502 is high among Han Chinese (5-15%), Malays (12-15%), and Thais (8-27%), but low among Japan, Korea, Sri Lanka, and most ethnic groups in India. Other than Han Chinese, the association between HLA B*1502 and carbamazepine-induced SJS-TEN is also seen among the Thais and Malay. There is urgent need for further studies to determine the prevalence of SJS/TEN, and BLA B*1502 in the various ethnic groups in Asia, and its association with carbamazepine-induced SJS-TEN in each of these ethnic groups. In view of the significant morbidity and mortality in SJS-TEN, facilities should be developed to allow for screening of HLA B*1502 before carbamazepine is prescribed to the Hans Chinese, Malays and Thais. For those who experience no adverse cutaneous reactidn after 3 months use of carbamazepine, the risk of SJS/TEN is low, and the drugs can be continued.