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Monilethrix
 Monilethrix
makes hair fiber look like a string of beads. Along the length
of a hair fiber there are nodes and constrictions making the edge
of
the fiber undulate. This hair beading weakens the fiber and people
with monilethrix have diffuse hair loss. Most frequently the hair
loss is at the back of the scalp and neck and can leave the front
of the head relatively unaffected. Monilethrix can also affect
hair
in other regions of the body.
Under a microscope the hair fibers can be seen to have lost
their cuticle covering over the nodes while the constrictions
keep their
cuticle. The brittle hair easily breaks once it is exposed above
the skin and the fibers rarely grow very long as a result. Breakage
occurs in the weak constriction points along the fiber.
Associated with the beaded hairs there can also be defects in
the hair follicle itself. The hair follicles may become keratotic
and defects develop in the root sheaths. Monilethrix can also be
associated with defects in the eyes (cataracts), teeth, and nails
all of which are structures with similar properties to hair follicles.
Treatment has been attempted with some success.
Monilethrix most often occurs in childhood but young adults can
also develop it. It can be genetically inherited with an autosomal
dominant pattern. Seasonal changes can be observed. It is worse
in winter and improves in summer. Monilethrix may spontaneously
improve without treatment.
Monilethrix
references
- Pearce
EG, Smith SK, Lanigan SW, Bowden PE. Two different mutations in
the same codon of a type II hair keratin (hHb6) in patients with
monilethrix. J Invest Dermatol. 1999 Dec;113(6):1123-7.
- Korge BP,
Hamm H, Jury CS, Traupe H, Irvine AD, Healy E, Birch-MacHin M,
Rees JL, Messenger AG, Holmes SC, Parry DA, Munro CS. Identification
of novel mutations in basic hair keratins hHb1 and hHb6 in monilethrix:
implications for protein structure and clinical phenotype. J Invest
Dermatol. 1999 Oct;113(4):607-12.
- Gebhardt
M, Fischer T, Claussen U, Wollina U, Elsner P. Monilethrix--improvement
by hormonal influences? Pediatr Dermatol. 1999 Jul-Aug;16(4):297-300.
- Winter
H, Clark RD, Tarras-Wahlberg C, Rogers MA, Schweizer J. Monilethrix:
a novel mutation (Glu402Lys) in the helix termination motif and
the first causative mutation (Asn114Asp) in the helix initiation
motif of the type II hair keratin hHb6. J Invest Dermatol. 1999
Aug;113(2):263-6.
- De Berker
DA, Ferguson DJ, Dawber RP. Monilethrix: a clinicopathological
illustration of a cortical defect. Br J Dermatol. 1993 Mar;128(3):327-31.
- De Berker
D, Dawber RP. Variations in the beading configuration in monilethrix.
Pediatr Dermatol. 1992 Mar;9(1):19-21.
- De Berker
D, Dawber RP. Monilethrix treated with oral retinoids. Clin Exp
Dermatol. 1991 May;16(3):226-8.
- Ito M,
Hashimoto K, Katsuumi K, Sato Y. Pathogenesis of monilethrix:
computer stereography and electron microscopy. J Invest Dermatol.
1990 Aug;95(2):186-94.
- Ito M,
Hashimoto K, Yorder FW. Monilethrix: an ultrastructural study.
J Cutan Pathol. 1984 Dec;11(6):513-21.
- Sivasundram A. A case of monilethrix treated
with etretinate. Dermatology. 1995;190(1):89.
- Saxena U, Ramesh V, Misra RS. Topical minoxidil
in monilethrix. Dermatologica. 1991;182(4):252-3.
- Tamayo L. Monilethrix treated with the
oral retinoid Ro 10-9359 (Tigason). Clin Exp Dermatol. 1983 Jul;8(4):393-6.
- Dawber RP. Weathering of hair in monilethrix
and pili torti. Clin Exp Dermatol. 1977 Sep;2(3):271-7.
- Hernandez-Perez E. Letter: Tretinoin therapy
for monilethrix. Arch Dermatol. 1974 Apr;109(4):575-6.
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