Evaluation of sensitivity of Tzanck smear in pemphigus

Background: Pemphigus is a group of immune-mediated, acantholytic disorders. Although direct immunofluorescence is the gold standard for the diagnosis of this group of diseases, it is not widely available and cost-effective in our country. Tzanck smear is a simple and easy test used to demonstrate acantholytic cells from the lesions of disease. The present study was planned to evaluate the sensitivity of Tzanck smear, in the diagnosis of pemphigus group of diseases. Patients and methods: Tzanck smears were prepared from 37 cases of active pemphigus (17 males and 20 females, age range 11-65 years), diagnosed by clinical, histopathological and direct immunofluorescence data. Patterns and positivity rate of Tzanck smears were recorded. Results: Overall sensitivity of Tzanck smears was 73%. Smears were positive in 75% of cutaneous lesions and 69% of mucosal lesions (p>0.05). Acantholytic cells were seen individually in all positive cases (100%), clumps (81%) and sheets (70%). Conclusion: Tzanck smears can be used as first-line investigation in our scenario. More sophisticated investigation e.g. direct immunofluorescence may be reserved for Tzanck-negative cases.