You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Twelve year old boy with vesicle over lip. Investigation to be done is and explain in detail?
Tzanck smear is a bed side test made by scrapping either floor of bulla( after deroofing). Or floor of erosion ( after removing crust). Or mucosal ( usually oral ) erosion . Stained with Giemsa stain. Acantholytic cells - rounded keratinocytes with relatively large nucleus and a condensed cytoplasm- seen in pemphigus group of disorders-pemphigus vulgaris and pemphigus foliaceous balloning degeneration and multinucleated gaint cells - seen in herpes simplex, herpes zoster and varicella iadvl textbook of dermatology, page 110