Which tests are most useful in evaluating vesiculobullous diseases?

Most of the tests helpful in determining the cause of vesiculobullous eruptions are performed on the blister itself. When infectious causes are being considered, appropriate cultures (aerobic bacteria, viruses, fungi) may be obtained, and smears from the blisters may be stained for bacteria, dermatophytes, or the multinucleate giant cells of herpes virus infections. For noninfectious vesiculobullous diseases, a skin biopsy is often a useful test.