How should a skin biopsy of a vesiculobullous eruption be performed?

The lesion for biopsy should be an early lesion, to avoid secondary changes that might make the diagnosis more difficult. A small, intact blister is a good choice, as the entire lesion and some of the surrounding skin can be removed in one piece. If a punch biopsy technique is used, it is important to avoid rupturing the blister. A small excisional biopsy is a good choice and minimizes the possibility of rupturing the blister. The specimen should be placed in 10% formalin and processed for routine histologic examination. Clinical information, including the age and sex of the patient, a description of the lesions, associated symptoms, and any exacerbating factors, should be provided, along with a differential diagnosis based on the clinical examination.