To the Editor In their JAMA Clinical Challenge, Drs Ladizinski and Lee1 presented a patient with herpes simplex virus (HSV)-induced erythema multiforme and suggested viral cultures or polymerase chain reaction (PCR) analysis of the oral vesicles to diagnose herpes. I would suggest a Tzanck smear first.
The test takes about 5 minutes to perform and to obtain an answer and has a high yield in the hands of an experienced dermatologist. It is inexpensive compared with viral culture or PCR, costing only a few dollars. If viral balloon cells are not found, a culture or PCR can still be ordered.
Miller RM. Diagnosis of Herpes Simplex Virus in Patients With Erythema Multiforme. JAMA. 2014;312(10):1060-1061. doi:10.1001/jama.2014.8739