Paint brush hair: a case report

INTRODUCTION

TN is a hair shaft disorder presenting with whitish nodes over the hair and could be either congenital or acquired. The acquired form is due to physical or chemical trauma which is more common than the congenital form.¹

Here, we reported a case of acquired TN of the beard caused due to repeated trivial trauma.

CASE REPORT

A 26 year old male presented to the dermatology outpatient department with history of multiple whitish spots over the beard hair since 3 months, with increased fragility at these spots (Figure 1). The patient admitted frequent brushing of his beard hair with a pocket comb. There was no history of bleaching, using hair cosmetics, or hair straightening. No similar lesions were seen on scalp hair or other hairy sites. No history of similar complaints in the family. Light microscopy and trichoscopy using videodermoscopy was done in beard hair which showed tiny nodules as thrust paint brushes as if two brushes were thrust into each other (Figure 2 and 3). Patient was advised to shave his beard hair and to avoid brushing completely. On follow-up, the patient was symptomatically better. Based on this, TN of the beard was diagnosed.

DISCUSSION

Acquired TN is a common hair shaft disorder associated with hair fragility due to cuticle repair as a response to thermal injury ,mechanical or chemical trauma.² The exposed cortical fibers separate and fray, causing a nodular swelling of the hair shaft at intervals. Individual cortical fibers start to fracture ,producing the appearance of two paint brushes thrust into one another.³

The condition is classified into an acquired form and a primary congenital form, which is usually associated with multi-system syndromes.^1,4

Acquired form results from excessive or repeated trauma caused by frequent brushing, scalp massage and repeated ultraviolet exposure and chemical trauma includes excessive salt water bathing, shampooing, setting and dyeing of hair.^3,5 It could also be due to malnutrition or endocrinopathy, especially iron deficiency and hypothyroidism.⁶ TN can also affect brittle hairs with underlying structural weakness apart from normal hairs like pili torti, monilethrix, pseudomonil- ethrix and trichorrhexis invaginata which are more susceptible to trauma.³ Characteristic presentation includes white flecking, dry and lustreless hair with abnormal fragility and inability to attain normal hair length because of premature breakage of the hair fiber.^1,4

Trichoscopy is one of the recent advances in diagnostic dermatology. It allows examination of subtle clinical patterns of skin lesions and subsurface skin structures not normally visible to the unaided eye.⁷ At low magnification, nodular thickenings along the hair shaft, which appear light in the darker hair shaft.⁴ At higher magnification, trichoscopy shows numerous small fibers, which produce a picture resembling two brooms or brushes aligned in opposition.⁴

Congenital TN is a rare condition that becomes apparent at birth or infancy.⁸ TN can be associated with argininosuccinic aciduria, Menkes' kinky hair syndrome, Netherton's syndrome, hypothyroidism or tricho-thiodystrophy.⁹ Common concurrent symptoms are mental retardation, motor defects, growth failure and seizures. Other associated symptoms may include nail and skin changes (ichthyosis), photosensitivity, ocular dystrophy and infertility.¹

Acquired TN falls into three basic categories: proximal, distal and localized.¹

Acquired localised

It generally is accompanied by a pruritic dermatosis such as seborrhoeic dermatitis, pediculosis capitis, contact dermatitis or lichen simplex, predominantly over scalp, beard or moustache, leading to repeated scratching. The hair is faded, lighter and lusterless. The condition eventually resolves spontaneously.³

Acquired proximal

It is common in blacks who use caustic chemicals while styling hair, causing breakage in the proximal hair shaft, leading to alopecia in areas subject to friction from brushing or sleeping.³

Acquired distal

It is common in white or Asian individuals, where the nodes appear on the distal ends of hair shaft, which looks lustreless and shows splitting.

Trichoscopically, trichorrhexis invaginata and hair casts can be considered as possible differential diagnosis.⁹ Clinically, differentials include dandruff, pediculosis and others shaft abnormalities like pilli annulate.1

Treatment options in acquired TN are aimed at avoiding the incriminated offending agent. The use of oils and conditioners can be advised to reduce the hair shaft cuticular damage by reducing the hair comb friction.¹⁰

CONCLUSION

TN is most commonly an acquired condition and recurrent mechanical trauma is a major contributing factor for hair shaft fragility. This case highlights the localised form of TN confined to the beard and the use of trichoscopy and light microscopy as diagnostic modalities in aiding the clinical diagnosis.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: Not required

REFERENCES

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