In what diseases is a skin biopsy helpful?

A skin biopsy with routine hematoxylin-eosin staining is the best diagnostic technique for many cutaneous neoplasms that cannot be diagnosed visually. It is also helpful in many inflammatory skin disorders, especially those in which a specific diagnosis cannot be made from clinical examination, blood tests, or scrapings of the skin. The skin biopsy is  a common office procedure, and specimens may also be submitted for more advanced studies such as immunofluorescence, electron microscopy, special stains, cultures, or polymerase chain reaction studies.