Association of hypermobility and ingrown nails

Ingrown nail (onychocryptosis) is a common condition with severe pain and various associated morbidities. Although some underlying factors are identified, its etiology remains largely unknown. Generalized joint hypermobility (GJH) is a common entity with clinical features that might prone affected individuals to ingrown nails. Herein, we investigated the incidence of GJH in patients with ingrown nails to determine possible association between hypermobility and ingrown nail formation. Patients 16-50 years of age who were undergoing treatment for ingrown nails at the dermatology clinic were consecutively enrolled into the study. Patients with known rheumatic diseases or orthopedic foot disorders were excluded. All patients were in a pain-free period at the time of examination. The control group was comprised of age- and sex-matched healthy subjects without a history of ingrown nail. Assessment of GJH was made according to Beighton criteria. Local hypermobility was evaluated by measurement of range of motion using a goniometer. Thirty-nine patients (male/female, 17/22, mean age 31.9 ± 11.3 years) and 32 healthy subjects (male/female 12/20, mean age 31.7 ± 10.4 years) were included. Patients with ingrown toe nails were more likely to have GJH compared to healthy subjects (35.9 vs. 9.4 %, p = 0.009). Toes with ingrown nails had significantly smaller maximum dorsiflexion angles (p < 0.001) compared to toes of healthy subjects. Ingrown nail formation may be associated with GJH. However, when examined locally, there is a limited range of motion in the affected toe rather than hypermobility, which could be due to the degenerative process facilitated by the hypermobility.