WINNIPEG, MAN. — Chronic paronychia is a variety of contact dermatitis that affects the proximal nail fold, so treating it with systemic antifungals is not useful, Dr. Antonella Tosti said at the annual conference of the Canadian Dermatology Association.
“Most people still believe that chronic paronychia is a candida infection. It is not,” said Dr. Tosti, professor of dermatology at the University of Bologna, Italy.
Instead, it starts with loss of the cuticle due to trauma or other causes, followed by irritation, immediate or delayed allergic reaction, or immediate hypersensitivity to food ingredients handled by the patient. Chronic paronychia is a common occupational problem among food workers, she said.
With the cuticle gone, environmental agents penetrate the proximal nail fold, causing inflammation in the nail matrix. Yeast and bacteria also may penetrate the proximal nail fold, leading to secondary colonization that may produce self-limited episodes of painful acute inflammation with pus. A green discoloration of the nail develops with colonization by Pseudomonas aeruginosa.
That's why clinicians may be able to culture bacteria or yeast, but treating with systemic antifungals will not cure the patient because it manages only the secondary problem, not the primary inflammation, Dr. Tosti said.
Chronic paronychia should be managed like contact dermatitis is treated, with hand protection and topical steroids, she advised. For patients with secondary candida colonization, recommend a high-potency topical steroid at bedtime and a topical antifungal in the morning. “I may use systemic steroids in severe cases” to provide fast relief of inflammation and pain, she added.
Chronic paronychia is shown before treatment with topical steroids.
The same patient is shown following treatment. Photos courtesy Dr. Antonella Tosti