BH17 A case of onychotillomania triggered by underlying inflammatory nail disorder

Abstract

Management of severe nail dystrophy can be clinically challenging when multiple aetiologies coexist. Here, we describe an interesting case in which primary nail dystrophy, initially attributed to psoriasis and allergic contact dermatitis (ACD), was further complicated by secondary onychotillomania, creating a challenging diagnostic and therapeutic loop. A 46-year-old female theatre nurse presented with severe, painful dystrophy involving all fingernails, on a background of scalp psoriasis and anxiety. Subsequently, patch testing confirmed ACD to thiuram mix found in work gloves containing rubber accelerators. Occupational health and line managers were involved to secure accelerator-free gloves, addressing the primary allergen exposure. Initial treatment with methotrexate and oral steroids helped with her symptoms and the nail dystrophy, but to a lesser degree. Following a multidisciplinary discussion and literature review, onychotillomania was suspected. Further history later revealed the patient’s persistent psychological distress from the initial, severe itch that had initiated a compulsive behaviour. She was habitually picking and rubbing the nails of her left hand against those of her right hand as a response to persistent psychological distress from pruritus, which perpetuated the damage. Further examination revealed features of onychotillomania, namely central nail erosion with nail plate destruction, multiple splinter haemorrhages and the presence of wavy lines. A dual-pathway treatment strategy was therefore employed. Methotrexate first addressed the primary inflammatory driver of the itch, followed by oral N-acetylcysteine to target the neuropsychiatric component of onychotillomania, as described in the literature. Onychotillomania is uncommon and can be misdiagnosed, and our case highlights that nail-linked inflammatory dermatoses can trigger secondary self-induced nail trauma. Persistent nail dystrophy despite treatment, especially in patients with significant psychological distress, should prompt evaluation for onychotillomania, and dermoscopy can be a helpful tool for diagnosis. Clinicians should be alerted to this comorbidity in refractory cases, notwithstanding the small number of cases reported thus far.