CASE #2: Habit-tic deformity

Habit-tic deformity is a traumatic nail dystrophy that results from habitual picking of the proximal nail fold margin.4 The most common location is the thumbnail; however, all fingernails can be affected. A longitudinal furrow with transverse parallel lines in the center is the characteristic finding.5 This is attributable to repeated back-and-forth picking of the thumbnail, typically by the nail of the index finger on the same hand. Other findings may include retraction of the proximal nail fold, hypertrophy of the lunula, or lichenification of the surrounding skin.

Patients who are burdened by psychiatric disease are most commonly affected by habit-tic deformity.6 In obsessive-compulsive disorder (OCD), the picking is part of a larger attempt to remove dirt and cleanse the skin. In association with body dysmorphic disorder, the patient’s thinking is centered on improving physical appearance. When the patient is unaware of the picking and performs the activity automatically, it more closely resembles trichotillomania, an impulse-control disorder characterized by a self-induced loss of hair caused by the continuous plucking of hair. Most patients, however, are aware of their picking, claiming it to be a nervous habit. Indeed, habit-tic deformity is more often present during periods of stress.

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A distinct but commonly confused condition for habit-tic deformity is median canaliform nail dystrophy (MCND). Whereas habit-tic deformity is caused by repeated nail trauma, the cause of MCND is unknown. An association with systemic isotretinoin has been reported, and familial occurrences have been documented. MCND is characterized by a longitudinal ridge in the center of the nail plate with tangential “fir-tree” depressions on either side. Guitar playing and personal-digital-assistant use have been reported to cause a median nail dystrophy similar in appearance to habit-tic deformity.7 In both instances, the dystrophy resolved itself within a few months after the patients discontinued the activity.

Other nail disorders in the differential diagnosis include chronic proximal nail-fold inflammation, onychomycosis, psoriasis, and Beau’s lines. In chronic paronychia, the affected nails exhibit rounded waves in contrast to the narrow grooves observed in habit-tic deformity. In addition, chronic paronychia is an inflammatory process associated with tenderness and swelling around the affected nail plates. Beau’s lines are deep-grooved lines that run horizontally across the fingernail and are thought to be a result of temporary cessation of cell division in the nail matrix. The lines are associated with chemotherapy, malnutrition, and such systemic diseases as diabetes, psoriasis, syphilis, and myocarditis.

Prognosis for habit-tic deformity is difficult to determine, as most of the literature on the disorder is in the form of isolated case studies. However, research on other self-inflicted dermatoses, such as trichotillomania and skin picking, suggest that these disorders often run a chronic course similar to their comorbid psychiatric disorders. A critical review of several studies in the 1980s reports that 52% of individuals found at the time to have skin picking continue this behavior at one year, with most having symptoms for 10-12 years.6

One successful treatment strategy described for patients with habit-tic deformity involves the use of fluoxetine (Prozac) for six months to one year, with an attempt to gradually taper the dosage after resolution of symptoms.8 Evidence suggests that skin-picking behavior is related to OCD, and since selective serotonin reuptake inhibitors (SSRIs) are approved for use in patients with this disorder, a strategy aimed at treating the underlying psychiatric cause appears appropriate. One case report describes a man with habit-tic deformity and symptoms of depression who underwent treatment with an SSRI. After four weeks of fluoxetine (20 mg/day), the patient stopped picking at his nail plate. He then went on to have complete resolution of his nail dystrophy.8

The efficacy of neuroleptic drugs in the treatment of such other tic disorders as Tourette syndrome suggests that their use might be effective in habit-tic deformity. However, neuroleptic drugs have considerably more serious side effects and can cause long-term irreversible tardive dyskinesia. No studies to date have evaluated their use in the treatment of habit-tic deformity. Multivitamins (Dermavite, one tablet/day) have also been reported to resolve cases of median nail dystrophy due to MCND and habit-tic deformity.4 Resolution was observed at four months, and on discontinuation of the multivitamin, ridging recurred within six months. Lastly, covering the proximal nail bed with tape during the day is another effective method for preventing the repetitive trauma to the nail plate. One case report describes moderate resolution of symptoms after two months of treatment.

The patient was not able to implement suggestions to stop rubbing her nails and cover the affected areas with tape, and the nail process remains unchanged.

Mr. Moses is a third-year medical student at Dartmouth Medical School in Hanover, New Hampshire. Dr. Scheinfeld is assistant clinical professor of dermatology at Columbia University in New York City, where he has a private practice. Neither author has any relationship to disclose relating to the content of this article.


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All electronic documents accessed September 13, 2010.