Oral minoxidil may have a role in young children with loose anagen hair syndrome

Hair & nails

By Michael Woodhead

24 Feb 2021

Young children with loose anagen hair syndrome (LAHS) can be safely and effectively treated with low-dose oral minoxidil, Australian dermatologists have found.

Dr Rebekka Jerjen and colleagues at Sinclair Dermatology, Melbourne, have described the successful treatment of eight girls aged from two to ten years of age with LAHS who were treated at their specialist hair clinic between March 2016 and October 2019.

After being diagnosed on the basis of clinical features, a positive hair‐pull test and findings on light microscopy, the children were  considered for oral minoxidil if they had failed topical minoxidil or their condition was associated with significant psychosocial distress.

Minoxidil was prescribed based on bodyweight (≤ 0·02 mg/kg once daily) with a mean dose of 0·24 mg, for seven to 26 months (mean 12.4).

All the patients showed reduction in hair shedding and improvement in hair length, while al but one had improvement in hair density. The improvements resulted in minoxidil treatment being discontinued in six patients whose hair was visibly denser and longer, while two were receiving ongoing treatment.

Oral minoxidil treatment also appeared to be well tolerated, with only patient developing mild hypertrichosis of the legs but opting to continue treatment. Although tachycardia, pedal oedema and hypotension have been reported in adults using minoxidil, there were no reported cardiac or respiratory symptoms or abnormal weight gain with the low doses used in normotensive children.

Two patients experienced a lightening in hair colour during treatment from reddish/dark brown to light brown.

Writing in the British Journal of Dermatology, Dr Jerjen said the improvements seen in young children were likely attributable to the 12 months of oral minoxidil treatment, since spontaneous improvement in loose anagen hair syndrome usually only occurred in adolescence.

“Our findings suggest that low dose oral minoxidil is a promising treatment for LAHS, particularly in children at the more severe end of the spectrum,” they wrote.

A possible mechanism of action for minoxidil in LAHS could be by promoting DNA synthesis and cell proliferation, they noted, thereby correcting the defective keratinization of the [inner root sheath] and improving anchorage of anagen hairs.

“While the above observations are reassuring, close monitoring is essential and low dose oral minoxidil should be reserved for patients who are psychologically affected by the appearance of their hair, and/or fail to respond to topical minoxidil or do not improve spontaneously with age,” they said.

“Treatment should be initiated and monitored by a dermatologist or paediatric dermatologist,” they added.

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