1) There is a strong association between the presence of HLA-B1502 and carbamazepine-induced SJS/TEN in Han-Chinese, Thai, and Malaysian populations.
2) The FDA has recommended screening patients of Asian ancestry for the HLA-B1502 allele before starting carbamazepine.
3) Overall, carbamazepine is the most common cause of SJS-TEN!
Also, take a look at this figure for a great DDx of short-lasting headaches!
Matharu MS, Goadsby PJ. Trigeminal autonomic cephalgias. J Neurol Neurosurg Psychiatry. 2002;72(Suppl II):ii19-ii26.