LAUSR

Median canaliform nail dystrophy and habit-tic deformity are nail abnormalities that may be on the same disease spectrum. However, coexistence of these two conditions is rarely observed. We describe a rare case of median canaliform nail dystrophy and habit-tic deformity coexisting in a patient with atopic dermatitis. A 58-year-old man with lifelong atopic dermatitis attended the dermatology trial clinic for routine followup. His atopic dermatitis was managed on an investigational Janus kinase inhibitor. His previous atopic dermatitis treatments included topical corticosteroids and phototherapy. His medical history included allergic rhinitis, allergic conjunctivitis, asthma and hypertension. The only medication in addition to the Janus kinase inhibitor was perindopril. On examination, his atopic dermatitis was reasonably well controlled. Complete skin examination incidentally revealed a left thumbnail with transverse lines involving the midline nail plate, while his right thumb demonstrated a pronounced median longitudinal groove accompanied by transverse fissures, giving the appearance of a fir tree (Fig. 1). Nail dystrophy in the setting of chronic paronychia was observed in other fingernails (Fig. 2). All nail changes were associated with macrolunulae and loss of cuticle. His toenails showed no abnormality. The remainder of the physical examination was unremarkable. On further questioning, the patient was right-handed and these nail changes had developed prior to participation in clinical trials. He reported habitual cuticle manipulation due to itch from atopic dermatitis. He denied any mood disturbance. There was no family history of nail diseases.