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CASE REPORT
Year : 2022 | Volume
: 42
| Issue : 2 | Page : 141-144
Median canaliform dystrophy of Heller: a report of three cases
Mitanjali Sethy MBBS, MD (Dermatology) , Venkatesh Mandava, Suvigya Sachan
Department of Dermatology, Venereology and Leprosy, Kalinga Institute of Medical Sciences, KIIT University, Bhubaneswar, Odisha, India
Correspondence Address:
Mitanjali Sethy
Department of Dermatology, Venereology and Leprosy, Kalinga Institute of Medical Sciences, KIIT University, Bhubaneswar 751024, Odisha
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/ejdv.ejdv_24_21
Median canaliform nail dystrophy of Heller (MCND), also known as dystrophia unguis mediana canaliformis, solenonychia, and nevus striatus unguis, is an uncommon nail disorder characterized by a paramedian or midline ridge or groove or canal formation in the nail plate of one or both the thumbnails. It rarely involves the other fingernails or toenails. Most of the cases of MCND are idiopathic. However, it may also be secondary to traumatic injury to the base of the nail, subungual skin tumors such as glomus or myxoid tumor, and the use of drugs like oral isotretinoin. Although it is believed to be an acquired condition, few familial cases have also been reported. Here we report three cases of MCND involving fingernails and toenails.
Keywords: Heller’s nail dystrophy, median canaliform nail dystrophy, median nail dystrophy, tacrolimus
Median canaliform nail dystrophy of Heller (MCND), also known as dystrophia unguis mediana canaliformis, solenonychia, and nevus striatus unguis, is a rare nail disorder, typically characterized by a midline or paramedian longitudinal ridge or groove or split on the nail plate of one or both thumbnails. Small depressions or transverse fissures extend laterally from the central canal, giving the appearance of an inverted fir tree or Christmas tree [1]. Heller was the first to describe this condition in 1928 [2].
Although majority of the cases are idiopathic, trauma to the base of the nail is considered in its pathogenesis. The treatment of this entity is often prolonged and unsatisfactory. Here we report three cases of MCND involving fingernails and toenails.
Case 1
A 21-year-old male came to the dermatology outpatient department with multiple depressions in both the thumbnails since 5 years and was concerned about the cosmetic appearance of nails. There was no history of biting of the thumbnails or any long-term intake of drugs or contact with any allergens or chemicals. He had no mental or physical illness. The patient did not have any family history of nail disorder. On examination, midline longitudinal depression with multiple transverse furrows arising from the midline depression on either side, resembling an inverted fir-tree pattern, was found on bilateral thumbnail plates ([Figure 1]). The lunulae of both thumbnails were enlarged. Mild scaling was present on proximal and lateral nail folds of bilateral thumbnails. Other fingernails and toenails were apparently normal. Skin and systemic examination were unremarkable. Potassium hydroxide (KOH) mount of the affected nail plates and subungual scrapings was negative for fungal hyphae. Histopathology was not done. Based on clinical findings, a diagnosis of MCND was made. He was put on twice-daily application of tacrolimus (0.1%) ointment.
Figure 1 Both thumbnails with midline longitudinal groove extending from proximal nail fold to the distal nail-plate edge with multiple small horizontal furrows radiating from either side of the groove, giving the appearance of an inverted fir tree. The lunulae of both thumbnails were enlarged.Case 2
A 19-year-old boy is presented to us with complaints of asymptomatic lesion over both thumbnails since 3 years. Upon careful history taking we found, the patient had a habit of biting of thumbnails and poking of thumbnails with pencils, pen, or objects with sharp tips during stress. No other inciting factor was found. He was otherwise healthy with no family history of nail disorder. On examination, there was the presence of median depression on both the thumbnails with transverse furrows extending from the median longitudinal groove ([Figure 2]). KOH mount prepared from the scraping of nails was negative for fungal elements. The patient refused biopsy. Diagnosis of MCND was made on clinical basis. He started twice-daily application of tacrolimus (0.1%) ointment, advised to avoid nail biting and trauma to nails, and sent for a psychiatry consultation.
Figure 2 Central longitudinal depression with fissures arising from either side of the depression of bilateral thumbnails.Case 3
A 20-year-old male presented to us with a complaint of asymptomatic multiple depressions on both great toenails since 6 years. He denied any history of trauma or contact with irritants or allergens to the affected nails or history of any prolonged drug intake or psychiatry illness. No similar disorder in any family member was detected. On examination, both the great toenails showed a midline longitudinal groove extending from proximal nail fold to the distal nail-plate edge with transverse furrows arising on either side of the midline groove ([Figure 3]). Exfoliation was present over both proximal and lateral nail folds of both great toenails. The rest other toenails and fingernails were apparently normal. KOH mount prepared from the scraping of nails was negative for fungal elements. The patient refused for biopsy. Based on clinical features, a diagnosis of MCND was made and he was given topical tazarotene (0.05%) ointment to apply.
Figure 3 Bilateral great toenails showing a symmetrical central linear groove with multiple parallel transverse fissures extending from the central groove and exfoliation of the skin over lateral and proximal nail folds of bilateral great toes. Discussion Median canaliform dystrophy of Heller is a rare nail disorder. It usually occurs in young adults or adolescents with a mean age of occurrence 25 years without predominance of sex [1],[3]. However, it has been reported in children also [4]. All the three cases of ours were young adolescent boys, we believe that the adolescent period is the most stressful part of life, during stress, patients may inflict trauma to the nail by manipulating the cuticular portion of the nail fold, resulting in MCND. However, such history could be elicited in only one out of three of our patients, while in the other two, we could not find any specific cause.
It is characterized by midline or paramedian longitudinal groove or split starting from the cuticle to the free edge of the nail plate with short transverse ridges or fissures that extend laterally from the central canal, giving the appearance of a Christmas tree or inverted fir tree, involving one or both thumbnails. MCND is usually bilaterally symmetrical and most commonly involves the thumb, however, other fingers or toes may be involved [2],[5]. In our case, out of three cases in two patients, thumbnails were affected, and in one patient, toenails were affected.
Although it is usually an acquired condition, few familial cases have been reported. As per our literature search, only four families with mother as a common member affected have been described [5],[6]. We could not elicit similar nail disorders among any of the family members of our three patients.
The exact etiology of MCND is still not known. Many causative factors have been implicated. Repeated trauma, especially manipulating the central part of the nail-matrix area or pushing back the cuticle and proximal nail fold, has been proposed as one of the causes [7]. Even weak trauma like repeated handwashing can act as an initial insult resulting in nail change [8]. It has also been reported following the habitual use of personal digital assistants [9] and after treatment of periungual warts with cryotherapy [10]. Few cases of MCND also reported in patients receiving oral aromatic retinoids, such as isotretinoin and the resolution of nail dystrophy, have been documented ∼4–6 weeks after discontinuation of the medication [11],[12],[13]. Few nail tumors such as myxoid and glomus tumors can cause longitudinal grooving, lifting of the nail plate from the bed, resulting in a tube-like structure (solenos) distal to it. Hence, MCND has also been referred to as solenonychia [6]. It is believed that a temporary defect in the matrix interferes with nail-plate formation, resulting in MCND [8].
Habit tic deformity, beau lines, lichen striatus, nail pterygium, nail-patella syndrome, and trachyonychia should be considered as differential diagnosis of MCND as all of these show longitudinal ridging of the nail plate [7]. The habit tic deformity is one of the common differentials, which produces transverse ridges along the central nail-plate depression instead of a longitudinal groove with lateral furrows as seen in MCND [14].
Histopathology shows parakeratosis and accumulation of melanin between the keratinocytes of the nail bed [8].
Treatment of MCND is quite challenging, as no therapy is consistently successful. Removal of the offending agents, such as rubbing or picking the nail, stoppage of drugs like oral isotretinoin to prevent the progression, is needed. Any underlying tumor if any needs to be removed. Opinion of a psychiatrist should be taken and treatment of psychiatric disorders like obsessive–compulsive or impulsive disorder or depression should be done to prevent further damage to the nail [15].
Triamcinolone acetonide injection into the matrix of the affected nail can be tried. However, it is usually painful and associated with adverse effects such as atrophy [16]. Kim et al. [8] successfully treated a case of MCND with once-daily application of topical 0.1% tacrolimus without occlusion for 4 months. It is believed that calcineurin inhibitors being anti-inflammatory agents interfere with the inflammatory component of MCND. However, we did not perceive significant improvement after 2 months of treatment with tacrolimus. Madke et al. [17] used topical tazarotene (0.05%) ointment to treat MCND as it acts by normalizing the process of keratinization. A complete cure of MCND with once-daily application of polyurea urethane 16% nail solution has been reported by Petrosian et al. [18]. They postulated that the polyurea urethane improves the integrity of the nail by adhering to keratin and thereby prevents unnoticed trauma to the nail plate. We advised twice-daily application of topical 0.1% tacrolimus to two patients and topical tazarotene (0.05%) ointment to one patient. Many times, MCND reverts to normal on its own without intervention, but the disease has a tendency to recur.
ConclusionMedian canaliform dystrophy of Heller is a mysterious entity and fascinates dermatologists by its unique morphology and resistant treatment. There are only a few published reports on MCND in the Indian literature. Scientific reporting of new cases not only adds to our knowledge but also helps to know the mechanism behind the development of such a clinical entity and in the counseling of anxious patients.
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