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

INTRODUCTION: Non-dermatology medical specialties may refer patients for skin biopsies, searching for a particular diagnosis. However, the diagnostic impact of the skin biopsy is not clearly established. This article aims to assess the indications for, and evaluate the clinical relevance of, skin biopsies in non-dermatology medical specialties. METHODS: A questionnaire was sent to 23 non-dermatology specialty departments in a university medical center, requesting a list of indications for skin biopsies, as well as to 10 staff dermatologists to collect the indications of skin biopsies requested by non-dermatology specialties. Once the indications were collected, a literature search was performed to evaluate their clinical value and relevance. RESULTS: Eleven non-dermatology specialties provided a list of skin biopsy indications, to which staff dermatologists added seven more indications. A literature search revealed evidence-based medicine data for six diseases, that is, amyloidosis, peripheral autonomic neuropathy, Sneddon’s syndrome, intravascular lymphoma, sarcoidosis, and chronic graft-versus-host disease. Results were questionable concerning infectious endocarditis, acute graft-versus-host-disease, and the lupus band test. Skin biopsy were not evidenced as useful for the diagnosis of calciphylaxis, systemic scleroderma, Behçet’s disease, or hypermobile Ehlers–Danlos syndrome. For the diagnosis of Alport’s syndrome, pseudoxanthoma elasticum, and vascular Ehlers–Danlos syndrome, skin biopsy is currently outperformed by genetic analyses. For diagnoses such as Henoch–Schönlein purpura and Sjögren’s syndrome, skin biopsy represents an additional item among other diagnostic criteria. CONCLUSION: The usefulness of skin biopsy as requested by non-dermatology specialties is only evidenced for amyloidosis, peripheral autonomic neuropathy, Sneddon’s syndrome, intravascular lymphoma, sarcoidosis, chronic graft-versus-host-disease, Henoch–Schönlein purpura, and Sjögren’s syndrome.