Monilethrix: a typical case report with microscopic and dermatoscopic findings* * Study conducted at the Instituto Fernandes Figueira - Fundação Oswaldo Cruz (IFF-FioCruz) – Rio de Janeiro (RJ), Brazil.

Elisa Fontenelle de Oliveira Ana Luiza Cotta de Alencar Araripe About the authors

Abstract

Monilethrix is a rare hereditary condition generally considered to be an autosomal dominant disorder with variable penetrance. A case of a 6-year-old girl without a familial background for this disease is reported. The diagnosis was made by optic microscopy and dermoscopy. A therapeutic trial with topical minoxidil was conducted.

Alopecia; Dermoscopy; Hypotrichosis


The term moniletrix comes from monile (necklace, in Latin) and thrix (hairs, in Greek). It is a rare, hereditary and autosomal dominant condition caused by mutations of the genes encoding trichocytes, hHb1, hHb3 and bHb6 type-2 keratins. It has been proposed that the hHb1 gene mutation produces a milder phenotype. The defect is located on chromosome 12q11q13.1Ferrando J, Galve J, Torres-Puente M, Santillan S, Nogues S, Grimalt R. Monilethrix: A New Family with the Novel Mutation in KRT81 Gene. Int J Trichology. 2012;4:53-5. It is characterized by the presence of elliptical nodes and intermittent constrictions on the hair shafts, resulting in hair fragility at those points.2Haliasos EC, Kerner M, Jaimes-Lopez N, Rudnicka L, Zalaudek I, Malvehy J, et al. Dermoscopy for the Pediatric Dermatologist Part I: Dermoscopy of Pediatric Infectious and Inflammatory Skin Lesions and Hair Disorders. Pediatr Dermatol. 2013;30:163-71. Clinical expression varies widely.1Ferrando J, Galve J, Torres-Puente M, Santillan S, Nogues S, Grimalt R. Monilethrix: A New Family with the Novel Mutation in KRT81 Gene. Int J Trichology. 2012;4:53-5. Normal hair is progressively replaced by abnormal one during the early months of life.3Vikramkumar AG, Kuruvila S, Ganguly S. Monilethrix: A Rare Hereditary Condition. Indian J Dermatol. 2013;58:243. Mutations in desmoglein 4 have been found in autosomal recessive forms.1Ferrando J, Galve J, Torres-Puente M, Santillan S, Nogues S, Grimalt R. Monilethrix: A New Family with the Novel Mutation in KRT81 Gene. Int J Trichology. 2012;4:53-5.

Clinical presentation may be very characteristic, with extremely short, fragile hair emerging from keratotic follicular papules, especially in the occipital region.4Olsen EA. Hair disorders. In: Irvine AD, Hoeger PH, Yan AC, editors. Harper's Textbook of Pediatric Dermatology. Oxford: Wiley-Blackwell; 2011. p. 148.9.

In milder forms, it may go unnoticed with few affected follicles. However, in serious forms, the secondary sexual hairs as well as the eyebrows and eyelashes may be compromised.1Ferrando J, Galve J, Torres-Puente M, Santillan S, Nogues S, Grimalt R. Monilethrix: A New Family with the Novel Mutation in KRT81 Gene. Int J Trichology. 2012;4:53-5.

The hair defect may occur in isolation or be associated with keratosis pilaris, syndactyly, cataracts, dental abnormalities and nail abnormalities.1Ferrando J, Galve J, Torres-Puente M, Santillan S, Nogues S, Grimalt R. Monilethrix: A New Family with the Novel Mutation in KRT81 Gene. Int J Trichology. 2012;4:53-5.,4Olsen EA. Hair disorders. In: Irvine AD, Hoeger PH, Yan AC, editors. Harper's Textbook of Pediatric Dermatology. Oxford: Wiley-Blackwell; 2011. p. 148.9.

It may cause scarring alopecia.1Ferrando J, Galve J, Torres-Puente M, Santillan S, Nogues S, Grimalt R. Monilethrix: A New Family with the Novel Mutation in KRT81 Gene. Int J Trichology. 2012;4:53-5.

Trichoscopy shows regular variations in the diameter of the hair shaft with elliptical dilations (nodes) and constrictions (internodes).4Olsen EA. Hair disorders. In: Irvine AD, Hoeger PH, Yan AC, editors. Harper's Textbook of Pediatric Dermatology. Oxford: Wiley-Blackwell; 2011. p. 148.9. Fusiform nodes are microscopically seen every 0.7-1 mm. Among the nodes, there is usually no hair marrow (medulla).5Rogers M, Tay YK, Wong LC. Hair disorders. In: Schachner LA, Hansen RC, editors. Pediatric Dermatology. Philadelphia: Mosby Elsevier, 2011. p. 752-3.

Hair shine may show improvements during the summer and with age. The use of topical minoxidil or oral acitretin may be effective in some cases. Initial improvement but with no lasting effect is described with the use of N-acetyl cysteine .3Vikramkumar AG, Kuruvila S, Ganguly S. Monilethrix: A Rare Hereditary Condition. Indian J Dermatol. 2013;58:243. Avoiding trauma to the hair is the most effective method in the management of this anomaly.3Vikramkumar AG, Kuruvila S, Ganguly S. Monilethrix: A Rare Hereditary Condition. Indian J Dermatol. 2013;58:243.

We report the case of a 6-year-old girl, born of a non-consanguineous marriage. She had two healthy sisters. Her normal hair had progressively been replaced by abnormal one during the early months of life. In fact, she never had a hair cut, due to its easily fragmentation and, consequently short length.

Clinical examination revealed diffuse hypotrichosis of the scalp, as well as coarse hair. Keratotic follicular papules were mainly observed in the occipital region (Figure 1). The diagnosis was confirmed by dermoscopy and optical microscopy, which demonstrated the appearance of “rosary beads”, with nodes and constrictions (Figures 2 and 3). She was referred for genetic evaluation and was prescribed minoxidil 2% solution. A few months after, we noticed an increase in the length of a few strands of hair, which did not have the previously described aspect (Figure 4).

FIGURE 1
Initial clinical aspect: diffuse hypotrichosis, coarse hair and keratotic follicular papules, especially in the occipital region
FIGURE 2
Dermoscopic aspect - hair looking like rosary beads, with nodes and constriction
FIGURE 3
Optical microscopy of a hair strand- hair looking like rosary beads, with nodes and constrictions
FIGURE 4
Final clinical aspect – A few months after the use of minoxidil - increase in the length of a few strands of hair

Conclusion: Monilethrix is a rare condition that can be identified through characteristic findings. Diagnosis may also be noninvasively made by dermoscopy and optic microscopy of the hair.

  • Financial funding: None
  • How to cite this article: Oliveira EF, Araripe ALCA. Monilethrix: a typical case report with microscopic and dermatoscopic findings. An Bras Dermatol. 2015;90(1):126-7.
  • *
    Study conducted at the Instituto Fernandes Figueira - Fundação Oswaldo Cruz (IFF-FioCruz) – Rio de Janeiro (RJ), Brazil.

REFERENCES

  • 1
    Ferrando J, Galve J, Torres-Puente M, Santillan S, Nogues S, Grimalt R. Monilethrix: A New Family with the Novel Mutation in KRT81 Gene. Int J Trichology. 2012;4:53-5.
  • 2
    Haliasos EC, Kerner M, Jaimes-Lopez N, Rudnicka L, Zalaudek I, Malvehy J, et al. Dermoscopy for the Pediatric Dermatologist Part I: Dermoscopy of Pediatric Infectious and Inflammatory Skin Lesions and Hair Disorders. Pediatr Dermatol. 2013;30:163-71.
  • 3
    Vikramkumar AG, Kuruvila S, Ganguly S. Monilethrix: A Rare Hereditary Condition. Indian J Dermatol. 2013;58:243.
  • 4
    Olsen EA. Hair disorders. In: Irvine AD, Hoeger PH, Yan AC, editors. Harper's Textbook of Pediatric Dermatology. Oxford: Wiley-Blackwell; 2011. p. 148.9.
  • 5
    Rogers M, Tay YK, Wong LC. Hair disorders. In: Schachner LA, Hansen RC, editors. Pediatric Dermatology. Philadelphia: Mosby Elsevier, 2011. p. 752-3.

Publication Dates

  • Publication in this collection
    Jan-Feb 2015

History

  • Received
    22 Oct 2012
  • Accepted
    28 Dec 2012
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