Unilateral Median Canaliform Dystrophy of Heller with Atopic Dermatitis: A Rare Finding

History and Clinical Findings A 14-year-old male patient presented at the dermatology outpatient department with itching over flexures and bilateral soles, on and off, for the past 3 years. During the physical examination, the patient's skin appeared dry and scaly [Figure 1], with hyperlinear palms and soles [Figure 2]. On nail examination, a midline longitudinal furrow with transverse ridges directed backward was noticed over the left great toe nail, without any involvement of the proximal nail fold [Figure 3]. The rest of the fingernails and toenails appeared normal. The patient's skin appeared dry, with hyperlinear palms and soles.Figure 1: Bilateral dorsum of the foot with dry scaly areas and left great toenail showing median canaliform dystrophy of HellerFigure 2: (a) Bilateral palms and soles showing hyperlinearity, (b) Bilateral hyperlinear palms and left great toenail with median canaliform dystrophy of HellerFigure 3: A midline longitudinal furrow with transverse ridges directed backwardly present in the left great toenailThere was no history of trauma, repeated rubbing, picking, or biting of the toenail by the patient. There was no history of a similar nail deformity in the parents. In addition, there was no history of oral retinoid intake, allergic rhinitis, or any food allergy. Discussion Median canaliform dystrophy (MCD) of Heller is a dystrophic condition of the nail. It is typically characterized by a split in the middle portion of the nail plate, usually with symmetrical involvement of the thumbnail, resembling a fir tree with the backward angles of branches.[1] We considered the closest differential diagnosis to be habit-tic deformity, which often shows a detached cuticle unlike MCD.[2] Therefore, the final diagnosis was MCD of Heller of the left great toenail. Declaration of patient consent The authors certify that they have obtained all appropriate consent forms, duly signed by the parent(s)/guardian(s) of the patient. In the form, the parent(s)/guardian(s) has/have given his/her/their consent for the images and other clinical information of their child to be reported in the journal. The parents understand that the names and initials of their child/children will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.