Nail-Picking and Biting: More Than Bad Habits

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Nail disorders can arise independently or manifest as part of systemic and dermatological diseases. Differentiating between primary nail pathology and self-induced nail disorders (SINDs) remains a complex yet essential component of dermatologic diagnosis. The nail unit, composed of the nail plate and surrounding structures, often reflects systemic and behavioral influences. Notably, individuals may induce nail damage through conscious or unconscious behaviors, sometimes acknowledging their role or, alternatively, denying their involvement.¹ These behaviors may lead to secondary complications such as infections or irreversible nail deformities.² Recent research stated accurate assessment of the physical changes in the nail structure is critical in identifying self-induced patterns versus organically arising nail disease.³

Background

Self-induced nail disorders are classified under body-focused repetitive behaviors (BFRBs), a group of conditions characterized by repetitive, habitual manipulation of the body. These behaviors are often triggered by feelings of boredom, tension, or anxiety, and while not driven by self-harm intentions, they may become compulsive due to the temporary relief they provide. BFRBs are recognized within the spectrum of obsessive-compulsive and related disorders (OCRDs) in the DSM-5 and ICD-11. The behaviors frequently target hair (trichotillomania), skin (excoriation disorder), lips, cheeks, and nails, with patients often presenting with multiple overlapping BFRBs.⁴

SINDs encompass a range of behaviors affecting the nail unit, including finger-sucking-related changes, habitual tic deformity (washboard nails), onychophagia (nail biting), onychotillomania (nail picking or pulling), and excessive grooming behaviors like over-filing or cuticle removal. Additionally, manipulation of artificial nails or nail polish is increasingly recognized as a distinct subtype, particularly in women. While SINDs are widespread, their impact on daily life may vary, and they are often underreported and undertreated, possibly due to societal normalization or a lack of awareness regarding treatment options.³

Methods

A multicenter prospective cohort study conducted from February to June 2024 analyzed 675 patients diagnosed with SIND. The study aimed to characterize the clinical and demographic features of individuals with these behaviors. Most participants were women (60.9%), and the average onset age of the disorder was during adolescence. The majority (87%) were right-handed, and in all cases, fingernails were affected. Roughly 47% of patients fell into multiple SIND subtypes, reflecting the often-complex behavioral patterns of BFRBs.

A significant proportion (56%) of patients expressed dissatisfaction with their behavior, citing cosmetic concerns, pain, embarrassment, or loss of control. Although nearly half had attempted self-intervention, only 19% had sought medical help. The study found women more frequently reported distress and were more likely to pursue treatment, though the difference was not statistically significant.

The presence of comorbid BFRBs was high (45.4%), and family history was positive in 27% of cases. Psychiatric comorbidity was also notable: 21.8% of participants had been diagnosed with at least 1 psychiatric condition, most commonly anxiety or depressive disorders. Patients with psychiatric diagnoses were significantly more likely to seek treatment, suggesting that mental health awareness may influence help-seeking behaviors.

Conclusion

The study stated the overlap of multiple BFRBs and psychiatric conditions underscores the importance of a holistic diagnostic approach. Behavioral interventions, supportive environments, and psychiatric assessment are crucial for effective management.

Dermatologists, often the first point of contact for such patients, must be equipped to recognize SINDs, provide supportive therapies, and facilitate appropriate referrals.

Although SINDs may appear benign or cosmetic, their impact on patient well-being can be substantial. Early recognition, patient education, and multidisciplinary care are key to improving outcomes for individuals affected by these behaviors.

References

1. Gupta MA, Vujcic B, Gupta AK. Dissociation and conversion symptoms in dermatology. Clin Dermatol. 2017;35(3):267-272. doi:10.1016/j.clindermatol.2017.01.003
2. Cohen PR. Nail-associated body-focused repetitive behaviors: Habit-tic nail deformity, onychophagia, and onychotillomania. Cureus. 2022;14(3):e22818. Published 2022 Mar 3. doi:10.7759/cureus.22818
3. GüldikenDoğruel G, Atış G, Esen M, et al. Self-induced nail disorders: Clinical and demographical features. Int J Dermatol. Published online April 10, 2025. doi:10.1111/ijd.17781
4. Madan SK, Davidson J, Gong H. Addressing body-focused repetitive behaviors in the dermatology practice. Clin Dermatol. 2023;41(1):49-55. doi:10.1016/j.clindermatol.2023.03.004