A nail-biting commentary

By Warren R. Heymann, MD, FAAD
Feb. 15, 2023
Vol. 5, No. 7

Reading advice columns has been a lifelong habit, having been enamored as a youth by the practical wisdom offered by “Dear Abby” (Pauline Esther Friedman Phillips) and her twin sister “Ann Landers” (Esther Pauline Friedman Lederer). Another long-standing habit, I’m embarrassed to admit, is nail-biting (onychophagia) — naturally I was intrigued by Carolyn Hax’s advice column in the Philadelphia Inquirer (syndicated from the Washington Post) entitled “Boyfriend is a ‘relentless’ nail biter. How to make him stop?” (1)

Question: My boyfriend is a relentless nail-biter. We have gotten into many spats about it because I think it's unhygienic and unflattering. He says he wants to change, but it has been years, and still he gnaws at his nails constantly. Any advice?

Answer: For him or you? He can get the underlying condition treated (anxiety, ADHD, OCD, other possible neuro issues), put foul-tasting stuff on his nails to treat the symptom, and redirect the fidget impulses. But does he want to? And if yes, will he follow through these steps? You can suggest that he do these things and, if he refuses, treat this as a take-him-or-leave-him-as-is proposition. Recurring arguments are refusals to take reality for an answer.

Overall, she is spot on, although I would be quite perturbed if my wife left me because of onychophagia!

According to Halteh et al: “Onychophagia is classified in the Diagnostic and Statistical Manual of Mental Disorders-V (DSM-V) and the International Classification of Diseases, Revision 10 (ICD-10). In the DSM-V, it falls under the sub-category of ‘Other specified Obsessive-Compulsive and Related disorders,’ specifically as a body-focused repetitive behavior (BFRB), which also includes lip biting and cheek chewing. To meet the criteria for this diagnosis, the patient must also repeatedly attempt to suppress or halt the activity, and it must have negative effects on their social and occupational life.” (2)

The prevalence of onychophagia is between 20% and 30% of the general population, increasing from childhood to adolescence with only rare cases reported in children under 3 years old. It decreases after puberty and progressively declines in adulthood but may persist in some adults (3). In a survey of 362 physicians, 24% reported nail-biting periods during their lifetimes, and 2% remained as active nail biters. (4)

There is a spectrum of how patients experience nail-biting. Baghchechi et al observe: “Some are consciously aware of their nail-biting habit, whereas others unconsciously bite their nails under specific triggers or circumstances.” (5) The etiology of onychophagia is unknown although genetic factors may be at play (it is more common in monozygotic than dizygotic twins). Onychophagia may be more common in those with psychiatric disorders, such as anxiety or obsessive-compulsive disorder. (2)

Shin et al examined the nails of 53 patients with onychophagia and observed the following: All 10 fingernails were affected in 37.7% of the patients. The left thumbnail was the most predominantly affected site (81.1%). Short nails with ragged distal borders were the most common presentation (100.0%), followed by generalized or patchy rough areas (50.9%), linear and pinpoint hemorrhage (32.1%), longitudinal melanonychia (30.2%), transverse groove (28.3%), brittleness (28.3%), macrolunula (24.5%), washboard nail (13.2%), and pterygium (3.8%). Of the patients, 88.7% had periungual complications, such as periungual exfoliation (77.4%), absent or ragged cuticle (52.8%), hyponychial hyperkeratosis (37.7%), and paronychia (15.1%). (6) (I could not resist — I examined my nails after reading this article. Yes, my nails were short, and the left thumbnail was affected the most!)

There are multiple potential complications of onychophagia, including shortening or loss of the nail, onychoschizia, chronic paronychia, infections, pterygium inversum unguis, splinter hemorrhages, melanonychia, and leukonychia. (7) Melanonychia may appear longitudinal. (8) Infectious complications include paronychia, a predisposition for herpetic whitlow, and facilitation of subungual verrucae. (2) Osteomyelitis, possibly requiring surgical management, is a severe complication. (9) Dental/oral medicine concerns include gingival injuries, increased incisal wear, apical root resorption, and temporomandibular joint problems. (7)

With a pertinent medical history, physical examination (skin, mucous membranes, and nails), and appropriate laboratory studies, clinicians should be able to differentiate onychophagia from psoriasis, lichen planus, melanonychia (due to other etiologies), and onychomycosis.

Managing onychophagia depends on the severity of the problem, if there are complications, how it affects a patient’s life, and the patient’s willingness to be treated. Non-pharmacologic methods include punishment (reprimands — stop it!), habit reversal (developing a competing response such as holding a pencil), aversive therapies (bitter-tasting nail lacquers — there are many to choose from), hypnotherapy, functional analysis therapy (“rewiring” a leaned behavior), rewarding positive behavior, or wearing a non-removable reminder (wrist band). Of the approaches listed, punishment is no more effective than placebo. (In my opinion, if someone reprimanded me publicly, I would likely bite my nails more to relieve the stress.) Pharmacologic options include serotonin reuptake inhibitors (SSRI), tricyclic antidepressants (TCA), N-acetyl cysteine (NAC), dopamine agonists, and lithium. (2,5) The only pharmacologic treatment demonstrating efficacy in a randomized double-blind placebo-controlled trial was NAC, however, it was not superior to placebo. (2) Depending on the individual circumstances, a multidisciplinary approach involving dermatologists, psychiatrists, dentists, and even orthopedic surgeons may be necessary.

Inevitably, today you will see patients who bite their nails. They may be too embarrassed to mention it, even if it concerns them. During my examination, if I see evidence of onychophagia, I will say “I see you’re a nail-biter like I am.” It is usually acknowledged with a gentle laugh, and I leave it at that. That opens the door for patients to ask for advice if they are interested. At least nobody has ever told me their spouse walked out on them over this problem.

Point to Remember: Nail-biting (onychophagia) is a common problem that can range in severity, with potential complications beyond the nails. Treatment, if desired, must be tailored to the patient with nonpharmacologic and pharmacologic approaches.

Our expert’s viewpoint

Rick Fried, MD, PhD, FAAD
Dermatologist/clinical psychologist
Clinical director
Yardley Dermatology Associates
Yardley Clinical Research Associates

Dr. Heymann’s nail-biting commentary highlights the significant prevalence of nail-biting and the potential for psychosocial impact. It is extremely important that clinicians, family, teachers, employers, and friends recognize that this is not a behavior that an individual “chooses” to perform. Nail-biting is similar to many of the other body-focused repetitive behaviors that are seen in dermatology patients (skin picking, trichotillomania, acne excorie’, prurigo nodularis, lichen simplex chronicus, etc.). All can occur in response to stress, boredom, dysesthetic symptoms, or a need to achieve an objective goal (even length nails, relief of inner tension, relief of itch, removal of a hair, etc.). Often, these behaviors can be functionally autonomous occurring with conscious awareness.

I strongly agree with Dr. Heymann that reprimand and punishment are not only ineffective, they are humiliating and usually provoke anger and subsequent worsening of the repetitive behavior.

In addition, supportive and empathic statements, together with “normalization” of their behaviors, stressing that the majority of people manipulate their skin, hair, and/or nails to varying degrees may be helpful. Framing the behaviors as “biologically based” can be a useful conceptualization helping patients to understand the etiology and persistence of the symptoms and also to facilitate acceptance of referrals to “skin-emotion specialists.” I have previously written that it is possible that body focused repetitive behaviors may be a “Forme frust” of Tourette’s Syndrome given the propensity in Tourette’s patients for repetitive and tic-like behaviors. As Dr. Heymann elucidated, behavioral therapies as well as pharmacotherapy can be effective in motivated individuals. Consideration of pimozide at very low doses of 0.5-2.0 mg can be very effective in controlling repetitive skin manipulation. Finally, patient desire for behavioral change is essential. This issue was eloquently presented by the following question: How many social workers does it take to change a lightbulb? It doesn’t matter, the bulb must want to be changed.

1. https://www.washingtonpost.com/advice/2022/03/01/carolyn-hax-boyfriend-nail-biting/

2. Halteh P, Scher RK, Lipner SR. Onychophagia: A nail-biting conundrum for physicians. J Dermatolog Treat. 2017 Mar;28(2):166-172. doi: 10.1080/09546634.2016.1200711. Epub 2016 Jul 7. PMID: 27387832.

3. Rizzo C, Sestino A, Pino G, Guido G, Nataraajan R, Harnish RJ. A Hierarchical Personality Approach Toward a Fuller Understanding of Onychophagia and Compulsive Buying. Psychol Rep. 2022 Feb 11:332941211061696. doi: 10.1177/00332941211061696. Epub ahead of print. PMID: 35147062.

4. Lesinskiene S, Pociute K, Dervinyte-Bongarzoni A, Kinciniene O. Onychophagia as a clinical symptom: A pilot study of physicians and literature review. Sci Prog. 2021 Oct;104(4):368504211050288. doi: 10.1177/00368504211050288. PMID: 34874802.

5. Baghchechi M, Pelletier JL, Jacob SE. Art of Prevention: The importance of tackling the nail biting habit. Int J Womens Dermatol. 2020 Sep 17;7(3):309–13. doi: 10.1016/j.ijwd.2020.09.008. Epub ahead of print. PMID: 32964094; PMCID: PMC7497389.

6. Shin JO, Roh D, Son JH, Shin K, Kim HS, Ko HC, Kim BS, Kim MB. Onychophagia: detailed clinical characteristics. Int J Dermatol. 2022 Mar;61(3):331-336. doi: 10.1111/ijd.15861. Epub 2021 Aug 20. PMID: 34416026.

7. Erdogan HK, Arslantas D, Atay E, Eyuboglu D, Unsal A, Dagtekin G, Kilinc A. Prevalence of onychophagia and its relation to stress and quality of life. Acta Dermatovenerol Alp Pannonica Adriat. 2021 Mar;30(1):15-19. PMID: 33765752.

8. Anolik RB, Shah K, Rubin AI. Onychophagia-induced longitudinal melanonychia. Pediatr Dermatol. 2012 Jul-Aug;29(4):488-9. doi: 10.1111/j.1525-1470.2011.01496.x. Epub 2011 Jun 22. PMID: 21692839.

9. Hoof M, Cognetti DJ, Mcclain WD, Plucknette B. Recurrent Osteomyelitis Requiring Surgical Management Secondary to Nail-Biting: A Case Report. JBJS Case Connect. 2021 Oct 6;11(4). doi: 10.2106/JBJS.CC.21.00346. PMID: 34613955.

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