The selection of the lesion to be sampled is an essential first step that greatly affects outcome.
If the blisters are surrounded by erythema, it is preferable to take two biopsies, one from the erythematous region and one from the normal skin
In the event of a skin disease that involves multiple typesof lesion or lesions that are in different stages of evolution, it is advisable to take several biopsies to cover allcontributing pathologies.