What is nail fold capillaroscopy? How is it useful?

is it useful? It is the in vivo examination of nail fold and cuticle finger capillaries, with magnification, to detect variations in capillary patterns. Autoimmune connective tissue disorders can have subtle but distinct changes within these capillaries and the proximal nail fold. It can be useful in predicting which patients with Raynaud’s syndrome will likely develop scleroderma. In those with scleroderma, the severity of capillary lesions may correlate with the degree of multisystem organ disease. Patients with dermatomyositis have capillary changes along with thickened, ragged cuticles. In systemic lupus, paronychial inflammation may be prominent with dilated tortuous capillaries distinctive.

Tosti A: The nail apparatus in collagen disorders, Semin Dermatol 10:71–76, 1991.