|Year : 2016 | Volume
| Issue : 2 | Page : 142-144
Loose anagen hair syndrome with diffuse woolly hair phenotype: A rare association
Arshdeep1, Rahul Mahajan2, Dipankar De1, Sanjeev Handa1
1 Department of Dermatology, Venereology, and Leprology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
2 Department of Dermatology, Venereology, and Leprology, All India Institute of Medical Sciences, New Delhi, India
|Date of Web Publication||30-Mar-2016|
Department of Dermatology, Venereology, and Leprology, Postgraduate Institute of Medical Education and Research, Chandigarh - 160 012
Source of Support: None, Conflict of Interest: None
Loose anagen hair syndrome (LAHS) is an underestimated cause of noncicatricial alopecia among children, manifesting as thin, sparse or fine hair. We report a case of LAHS clinically presenting as diffuse woolly hair, an association rarely described in the literature. In addition, we review the clinical as well as genetic link between these two enigmatic hair disorders and hypothesize that both may be associated in a yet unknown manner.
Keywords: Loose anagen hair syndrome, Noonan syndrome, woolly hair
|How to cite this article:|
Arshdeep, Mahajan R, De D, Handa S. Loose anagen hair syndrome with diffuse woolly hair phenotype: A rare association. Indian J Paediatr Dermatol 2016;17:142-4
|How to cite this URL:|
Arshdeep, Mahajan R, De D, Handa S. Loose anagen hair syndrome with diffuse woolly hair phenotype: A rare association. Indian J Paediatr Dermatol [serial online] 2016 [cited 2020 May 27];17:142-4. Available from: http://www.ijpd.in/text.asp?2016/17/2/142/175656
| Introduction|| |
Akeratinization defect of the inner root sheath resulting in improper anchorage of the anagen hair into the follicular unit constitutes the loose anagen hair syndrome (LAHS). It is one of the uncommon, yet easily diagnosable causes for noncicatricial alopecia in pediatric population, manifesting mainly as thin, sparse or fine hair. Herein, we report a case of LAHS clinically presenting as diffuse woolly hair, an association rarely described in the literature. In addition, we review the clinical as well as genetic link between these two enigmatic entities.
| Case Report|| |
A 2-year-old girl presented with short kinked hair all over scalp since birth. Her mother complained that the hair were not only difficult to comb, but also they did not grow long in spite of being never cut. In addition, hair were also easily pluckable. The child was otherwise systemically well with no family history of any hair disorder. On examination, diffuse, thin, lusterless curled hair were noted with tight frizzy coils [Figure 1]. The sparseness of hair was present particularly on the frontoparietal scalp. Hair pull test was strongly positive. Light microscopy of plucked hairs revealed >50% anagen hair, with ruffled cuticle stemming from mishappen hair bulbs, thereby giving a characteristic “floppy socks appearance” [Figure 2]. Potassium hydroxide mount of the hair shaft was negative. The rest of the examination including eyebrows, eyelashes, other body hairs, palms, soles, nails, and teeth was normal. Electrocardiography and echocardiography were unremarkable. The child was administered minoxidil 2% lotion for twice daily application with which she showed an improvement in hair density on the follow-up. However, the looseness persisted.
|Figure 1: Scalp showing diffuse, thin, lusterless curled hair with tight frizzy coils and sparseness on the frontoparietal area|
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|Figure 2: Light microscopy showing mishappen anagen hair bulb and ruffled cuticle, giving a characteristic “floppy socks appearance”|
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| Discussion|| |
LAHS may not be as rare as thought but is definitely more often misdiagnosed, especially if a simple bedside hair microscopy is bypassed and the patient is subjected to only blood investigations. A recent study of 374 children referred for alopecia over a 10-year period observed that nearly 10% of patients were diagnosed with LAHS. It may present sporadically or more commonly inherited as an autosomal dominant disorder with variable penetrance with onset in children typically below 3 years. Dyskeratotic changes have been demonstrated in the cuticle cells of both inner root sheath and hair shaft, which compromises the interdigitation between them. This allows anagen hairs to be pulled out painlessly with gentle traction only, thereby outnumbering telogen hairs on trichogram. Clinical features described in LAHS include light-colored hairs that do not grow long; diffuse thinning with hairs of uneven length or bald patches as a result of large clumps of hair pulled out.,, The hair texture is commonly described as thin, sparse, and fine. A subset of patients has “sticky” or “matted” hair, particularly in the occipital region, the area being subjected to constant friction., True “uncombable spun glass hair” have also been associated. However, LAHS associated with diffuse woolly hair as seen in our patient has been reported very rarely., Woolly hair itself is a rare, congenital structural abnormality of scalp hair in which the hair growth rate is usually normal, but the anagen phase is truncated, resulting in shorter hair. García-Hernández et al., first reported the association of late onset LAHS with congenital woolly hair predominantly over the occipital scalp in a 17-year-old woman. Chapalain et al., found diffuse partial woolly hair, in which woolly hair were diffusely intermingled with normal and loose anagen hair in two out of 17 children with LAHS. However, our patient presented with diffuse woolly hair all over the scalp, which on trichogram revealed the presence of LAHS in addition. The increase in hair density achieved with minoxidil in this child is in accordance with the literature while the looseness and woolly hair texture tended to persist.
As we review the literature, woolly hair and LAHS seem to be related since both conditions present a similar clinical scenario such as an early age at onset, female predominance, thin, sparse, and short hair and longitudinal grooves on microscopic examination. Both loose anagen hair and woolly hair are recognized cutaneous features of syndromes arising from abnormalities of the RAS/mitogen-activated protein kinase signaling pathway, particularly Noonan syndrome (NS) and cardio-facio-cutaneous (CFC) syndrome. Linkage analysis in these so-called “RASopathies” has found that patients with SHOC2 mutations in NS have a specific phenotype associated with loose anagen hair. Those with a pathogenic SOS1-associated NS are more likely to have CFC syndrome-like skin findings including woolly hair, palmoplantar hyperkeratosis, and keratosis pilaris. This data not only suggests that these two hair disorders are phenotypic markers of “RASopathies” but their association as seen in our patient may not be merely coincidental. This genetic link is further supported by findings from Chapalain et al., who found a keratin mutation E337K in K6HF gene in three of the nine families with LAHS, out of which two had associated diffuse partial woolly hair phenotype. More recently, mutations in lipase H or the LPAR6 (P2RY5) gene, encoding a G-protein coupled receptor, have been shown to be responsible for autosomal recessive woolly hair. Collectively, in light of a clinical and genetic link along with co-occurrence of these two hair conditions, we support the view that there is a significant link between them. These above-mentioned genes could be the potential candidates for further exploring the possibility of an association between these two enigmatic hair disorders.
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Conflicts of Interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]