Dermatodaxia or compulsive skin biting

Dear Editor,

Body-focused repetitive behaviors (BFRBs) are repetitive, injurious, and non-functional habits that cause significant distress or impairment. The term “dermatodaxia” is used to describe the act of skin biting and is classified under obsessive-compulsive disorders. It described the behavior of compulsively gnawing or biting at skin. It is a type of body-focused repetitive behavior commonly seen to involve the skin over the hands, fingers, or forearms. Previously patients with this condition were termed as wolf-biters because wolves are known to bite themselves when they feel frustrated. This was followed by the term dermatophagia which is now replaced with the term “dermatodaxia”. Psychological distress can present as cutaneous manifestations of mild dermatitis, skin cutting, deliberate self-harm, burning, and severe excoriation. Dermatophagia typically targets the skin surrounding the fingers and occasionally other visible areas of the body. Individuals who engage in skin biting, and in some cases, skin ingestion, are infrequently encountered in psychiatric contexts, potentially due to a lack of awareness about their condition or a desire to avoid the societal stigma associated with mental illness. Nevertheless, persistent and severe skin biting can lead to dermatological issues and permanent disfigurement. Additionally, this compulsive behavior exacerbates feelings of anxiety and discomfort, perpetuating a harmful cycle for the individual.[1]

A 10-year-old male, studying in the 6^th grade, was referred for psychiatric evaluation with complaints of repetitive and uncontrollable biting of the skin over the knuckles of both his hands and nail-biting for the past 3 years. His mother reported that the patient often sits for hours together, lost in thought, biting, and picking at the skin over his knuckles, and around his nails, and biting his nails as well for the past 3 years. His mother also reported temper tantrums, stubborn behavior frequent arguments, and physical quarrels with his elder sister for the past 2-3 months.

The patient’s elder sister has an intellectual disability. In school, he has good relationships with teachers and peers, with above-average scholastic performance. The mother revealed that the patient is excessively worried and particular when it comes to scholastics and exams. Physical examination revealed lichenified nodules over the proximal and distal interphalangeal joints of both his hands [Figure 1]. A mental status examination revealed a child sitting on the edge of his stool, increased motor activity, the mood was conveyed as “worried”, and the affect was anxious. Insight was 3/5 and judgement intact. This patient was started on Fluoxetine 10 mg and advised follow-up but did not report again.

Figure 1.

Lichenified nodules over the proximal and distal interphalangeal joints of both his hands

In addition to occurring alone, dermatodaxia can also occur in conjunction with other body-focused repetitive behaviors. A study on 4,435 undergraduate university students revealed that in the previous or current month, 72% (3,185 pupils) had engaged in a body-focused repeated behavior suggesting that such behaviors are not only common they are also chronic.[2] In a case series of sixteen patients, seven demonstrated nail-biting, six patients presented with skin nodules on their hands and fingers, and two had pigmented, dermatitis-like patches on the dorsal aspect of their hands.[1] Such behaviors do seem to be the result of significant anguish and distress, often increasing at the height of anxiety and used by the patient as a maladaptive coping technique to feel relief temporarily [Table 1]. For our patient, the repetitive behavior was his way of dealing with the deteriorating environment in his household due to recurrent conflicts as well as academic stress. Apart from oral medications, habit reversal therapy, and decoupling therapy have proved effective in the treatment of body-focused repetitive behaviours’ as was seen in our patient.

Table 1.

Summary of case reports of dermatodaxia or compulsive skin biting

Authors	Age/Gender	Stress	Lesion	Treatment
Moritz S[3] (2020)	50 years Male	History of skin picking and skin biting since early childhood.	Skin picking and biting especially around the nail of his thumb often led to bleeding and scarring.	Habit reversal therapy, decoupling therapy.
Cohen PR[4] (2022)	41 years Male	Past history of depressive symptoms.	Asymptomatic 12 x 12 mm scaly hyperkeratotic nodule between the knuckles of his proximal and distal interphalangeal joints on his left hand.	The patient did not want to consider any behavioral, physical, or systemic intervention.
Kubaisi TA[5] (2023)	14 years Male	Compulsive habit after which he would feel relaxed and enjoy this habit.	Asymptomatic multiple lichenified firm papules with calluses formation, and skin dyspigmentation, involving the dorsum of both hands and the distal part of the forearms	A psychiatric referral was advised.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Author's contribution

Concept, design, definition of intellectual content, AP, SC, AJ, PG. Literature search, data acquisition: AP, PG Manuscript preparation: AP, PG. Manuscript editing and manuscript review. SC. Guarantor: AJ.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.