The Relevance of Skin Biopsies in General Internal Medicine: Facts and Myths

Introduction: Non-dermatology medical spe-cialties may refer patients for skin biopsies, searching for a particular diagnosis. However, the diagnostic impact of the skin biopsy is notclearly established. This article aims to assessthe indications for, and evaluate the clinicalrelevance of, skin biopsies in non-dermatologymedical specialties. Methods: A questionnaire was sent to 23 non-dermatology specialty departments in a uni-versity medical center, requesting a list of indi-cations for skin biopsies, as well as to 10 staffdermatologists to collect the indications of skinbiopsies requested by non-dermatology spe-cialties. Once the indications were collected, aliterature search was performed to evaluate theirclinical value and relevance. Results: Eleven non-dermatology specialtiesprovided a list of skin biopsy indications, towhich staff dermatologists added seven moreindications.Aliteraturesearchrevealedevidence-based medicine data for six diseases,that is, amyloidosis, peripheral autonomicneuropathy, Sneddon’s syndrome, intravascularlymphoma, sarcoidosis, and chronic graft-ver-sus-host disease. Results were questionableconcerning infectious endocarditis, acute graft-versus-host-disease, and the lupus band test. Skin biopsy were not evidenced as useful for thediagnosis of calciphylaxis, systemic sclero-derma, Behc ̧et’sdisease, orhypermobileEhlers–Danlos syndrome. For the diagnosis ofAlport’s syndrome, pseudoxanthoma elasticum, and vascular Ehlers–Danlos syndrome, skinbiopsy is currently outperformed by geneticanalyses. For diagnoses such as Henoch–Scho ̈nlein purpura and Sjo ̈gren’s syndrome, skin biopsy represents an additional itemamong other diagnostic criteria. Conclusion: The usefulness of skin biopsy asrequested by non-dermatology specialties isonly evidenced for amyloidosis, peripheralautonomic neuropathy, Sneddon’s syndrome,intravascular lymphoma, sarcoidosis, chronicgraft-versus-host-disease, Henoch–Scho ̈nleinpurpura, and Sjo ̈gren’s syndrome.