Dactylitis, a term for different digit diseases

Abstract

Dorland's Illustrated Medical Dictionary gives the following definition of dactylitis (δάχτύλος = digit): ‘inflammation of a finger or toe’. Although any inflammatory process involving the fingers or toes may be called dactylitis, the term has entered in current use only in some well‐defined entities. These differ in the involved tissue of the digit and in the type of involvement. Tuberculous dactylitis is the variant of tuberculous osteomyelitis affecting the short tubular bone of the hands and feet. Radiographs typically show a central, lytic, cystic, and expansive lesion known as spina ventosa. Syphilitic dactylitis is a manifestation of congenital syphilis. Radiological findings mimic those of tuberculous dactylitis but the involvement is bilateral and symmetric. Sarcoid dactylitis is due to typical non‐caseating granulomas invading the phalanges and the adjacent soft tissue. Blistering distal dactylitis is an infection of the anterior fat pad on the volar surface of the distal portion of a single finger or more rarely a toe, mostly caused by group A β‐haemolytic streptococci. Sickle cell dactylitis, also known as ‘hand–foot syndrome’, is due to localized bone marrow infarction of the carpal and tarsal bones and phalanges. Spondyloarthritis dactylitis, also called ‘sausage‐like’ digit, is a diffuse painful swelling of the fingers and toes. Recent ultrasonography (US) and magnetic resonance imaging (MRI) studies on both finger and toe dactylitis have established that dactylitis is due to flexor tenosynovitis and that the enlargement of the joint capsule is not an indispensable condition for the ‘sausage‐like’ feature. There is no evidence of enthesitis of flexor digitorum tendons and joint capsule.