|Year : 2020 | Volume
| Issue : 1 | Page : 56-58
Monilethrix: A rare case diagnosed by dermoscopy
Aditya Rajendra Holani, Nishigandha S Haridas, Nirali G Shah, Nitin Chaudhari
Department of Dermatology, Smt. Kashibai Navale Medical College and General Hospital, Pune, Maharashtra, India
|Date of Submission||02-Dec-2019|
|Date of Decision||03-Sep-2019|
|Date of Acceptance||27-Nov-2019|
|Date of Web Publication||24-Dec-2019|
Dr Aditya Rajendra Holani
Department of Dermatology, Smt. Kashibai Navale Medical College, Narhe, Pune, Maharashtra
Source of Support: None, Conflict of Interest: None
Monilethrix is a rare genodermatosis characterized by hair shaft dysplasia, which is responsible for hypotrichosis. We present the case of a 2-year-old female, with involvement of the scalp, eyebrows, and eyelashes, in whom dermoscopy enabled a rapid diagnosis of monilethrix. Dermoscopy revealed the zones of intermittent constriction of the hair shaft, separated by elliptical nodes at regular intervals, giving the appearance of a characteristic “regularly bended ribbon” sign. This helped in differentiating it from pseudomonilethrix and other causes of hypotrichosis.
Keywords: Alopecia, beaded hair, dermoscopy, monilethrix
|How to cite this article:|
Holani AR, Haridas NS, Shah NG, Chaudhari N. Monilethrix: A rare case diagnosed by dermoscopy. Indian J Paediatr Dermatol 2020;21:56-8
|How to cite this URL:|
Holani AR, Haridas NS, Shah NG, Chaudhari N. Monilethrix: A rare case diagnosed by dermoscopy. Indian J Paediatr Dermatol [serial online] 2020 [cited 2020 Jun 1];21:56-8. Available from: http://www.ijpd.in/text.asp?2020/21/1/56/273840
| Introduction|| |
The term “monilethrix” is derived from the Latin word “monile” meaning “necklace” and the Greek word “thrix” meaning “hair.” The first case of monilethrix was described by Walter Smith in 1879, “as a rare nodose condition of hair.” However, the term “monilethrix” was coined by Radcliff Crocker. Monilethrix is transmitted as an autosomal dominant trait with high penetrance but variable expressivity. However, there are a few sporadic cases with autosomal recessive inheritance reported in the literature. It is characterized by localized or widespread dystrophy of the hair shaft causing patchy or diffuse hair loss. The hair shaft shows regular variation in diameter, producing alternate “nodes” and “internodes” which confer a characteristic beaded or moniliform appearance to the hair. Clinically, it may present with a varying degree of severity ranging from dystrophic hair confined only to the occiput to total alopecia. Monilethrix may be associated with keratosis pilaris, leukonychia, koilonychia, dental, ophthalmic anomalies, and metabolic abnormalities.
| Case Report|| |
A 2-year-old female born of a nonconsanguineous marriage presented to us with a history of decreased hair growth, increased hair fragility, and sparsity of the hair over the scalp and eyebrows since birth. The parents stated that the hair used to break on growing a few millimeters to the scalp surface. There was no similar history in any of the family members.
Clinical examination revealed diffuse alopecia involving the whole scalp and eyebrows [Figure 1]a and [Figure 1]b. Multiple small keratotic papules were noted on the scalp, nape of the neck, bilateral arms, and elbows. The scalp was gritty on palpation.
|Figure 1: (a) Diffuse alopecia involving the scalp and eyebrows. (b) Keratotic papules on the occipital region and the nape of the neck|
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A developmental examination of the child showed normal features. There were no nail, dental, sweat gland, ophthalmic, or other systemic abnormalities. There were no hematological abnormalities noted in routine workup. Her serum copper and ceruloplasmin levels were also normal. The examination of the parents and the elder brother was unremarkable.
Trichoscopy was performed with a handheld ×10 contact dermoscope (Dermlite Dl3N). Trichoscopy of the scalp revealed the presence of small, broken hair fragments of varying lengths along with numerous perifollicular white dots [Figure 2]. Examination of the eyebrows revealed characteristic beaded appearance of the hair. They showed bending in different directions with a tendency to break at internodes revealing the “regularly bended ribbon sign.” Varying lengths of hair and breakage at different levels from the skin surface were also appreciated [Figure 3]a and [Figure 3]b. Examination of eyelashes revealed distal breakage and typical beading in a few vellus hairs [Figure 4]. The diagnosis of monilethrix was adopted on the basis of these specific features.
|Figure 2: Trichoscopy of the scalp showing small, broken hair fragments of varying lengths, along with numerous perifollicular white dots|
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|Figure 3: (a and b) Trichoscopy of eyebrows showing hair beading and breakage at different levels. Affected hairs bend in different directions revealing the “regularly bended ribbon sign”|
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|Figure 4: The eyelashes show distal breakage and typical beading in a few vellus hairs|
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The parents were counselled regarding the nature of the disease. She was started on Biotin supplements, and the need to avoid trauma to the hair was emphasized.
| Discussion|| |
Monilethrix, a genodermatosis, is caused by a mutation in the hair keratin genes. In majority of the cases, it is due to mutations in the keratin gene type II encoding hHb1, hHb3, and hHb6 present over chromosome 12q11-q13. An autosomal dominant inheritance pattern is seen with the mutation in hair keratin genes KRT81, KRT83, or KRT 86. An autosomal recessive form has also been described and is caused by the mutation of the gene DSG4 coding for desmoglein 4. The most frequent mutation is E413 and hHb6. The diagnosis of monilethrix was more difficult to establish in our patient owing to the absence of any familial cases. One probable reason is that it might be an autosomal recessive form of the disorder. As penetrance of the disease is also variable from one subject to another, the diagnosis may have been missed in one of the two parents despite a thorough examination.
The diagnosis of monilethrix is essentially clinical, usually confirmed by microscopy of the hair shaft or histology showing abnormal hair follicles with alternating constricted and normal portions in a few cases. The hair shaft appears normal at birth, but soon thereafter, nodes begin to form along the hair shaft at regular intervals of 0.5–1 mm. This is probably related to external trauma. Recent studies have demonstrated the abnormalities of the cuticle, cortex, and keratinizing zones of the hair follicles. There is a considerable variation in the age of onset and the extent of involvement. The short and stubble brittle hair is more prominent on the occipital region and is seen emerging from the top of the horny follicular papules. The condition usually remains confined to the scalp, but other areas such as the eyebrows, eyelashes, axillary hair, pubic hair, and the hair on the rest of the body can also be involved.
Trichoscopy is much easier and less time-consuming than ex vivo microscopic examination, and the latter was not performed in this patient because of the inadequacy of the sample. The characteristic trichoscopic feature is “regularly bended ribbon sign” with periodic alteration of constrictions (defect) and nodes (real hair diameter) causing the characteristic beading. The nodes seem to represent the normal growth, and the internodes are characterized by the wrinkling of cortical cells leading to fragility of the hair with an absence of the medulla. In addition, perifollicular keratotic papules may be visualized. The presence of these typical signs in our patient was immediately suggestive of the diagnosis.
In general, monilethrix is not associated with any systemic disturbances. However, a few rare cases have been reported with trichorrhexis nodosa, physical/mental retardation, juvenile cataracts, teeth and nail abnormalities, syndactyly, and metabolic abnormalities (aminoaciduria). The course and outcome of this condition are very unpredictable. It may persist throughout life or spontaneous partial or complete remission can occur with age. An improvement during adolescence and pregnancy has been documented, suggesting a hormonal influence. There is no effective way to treat monilethrix. Many single-case reports showing improvement with topical 2% minoxidil, biotin, iron supplements, N-acetyl cysteine, acitretin, steroids, oral contraceptive pills, and griseofulvin have been reported.,, The avoidance of trauma remains the cornerstone of management of this hair disorder. Artificial hairpieces or wigs for better cosmesis can also be considered.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initial will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]