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Toenail thickening

A 59-year-old woman presented to her family physician (FP) with a 2-year history of toenail thickening of the left great toe, as well as discomfort when wearing certain shoes. The patient had already tried a 3-month course of oral terbinafine and had been using a topical antifungal for nearly a year, but neither had helped. The patient denied any history of trauma to the toenail.

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Toenail thickening

The FP suspected onychauxis, more commonly called hypertrophic nail. The patient’s toenail had the characteristic features of onychauxis, which include discoloration (usually yellow or brown) and a dull appearance. Often, there is an increased curvature or deviation of the nail and a “clam shell” appearance with transverse lines or a lamellar pattern like a ram’s horn. This is in contrast to the longitudinal lines and furrows that one would see with brittle nails associated with old age or the longitudinal melanonychia (hyperpigmented lines) seen in melanoma. Trauma to the nailbed, including trauma from ill-fitting shoes, is the most common cause of onychauxis.

Although nail discoloration and thickening raise the concern for onychomycosis, not all thickened and discolored nails are due to fungal infection. In this case, the thickening of the nail itself (as opposed to the subungal hyperkeratosis typical of onychomycosis) and a lack of improvement with antifungal treatment prompted the FP to consider other causes of nail dystrophy besides onychomycosis.

Nail trimming and filing can minimize discomfort and limit nail margin trauma caused by the nail’s abnormal shape. If this does not provide relief, the curative treatment for onychauxis is toenail removal and matrix ablation. In this case, the patient chose to defer nail removal and resection of the matrix. She said she would consider this treatment option if her nail became more bothersome.

Photos and text courtesy of Sabrina Gill, MD, and Daniel Stulberg, MD, FAAFP, Department of Family and Community Medicine, University of New Mexico School of Medicine, Albuquerque.

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