Infants Exposed to Minoxidil May Develop Hypertrichosis

In April 2023, the Navarra Pharmacovigilance Center (NPC) became aware of a case involving an infant who developed progressive hair growth on their back, legs, and thighs (hypertrichosis) over the course of 2 months. During an interview with the family, it was revealed that the infant’s father had been using 5% topical minoxidil to treat androgenic alopecia, and he had taken a leave of absence from work to care for his child. After the medication was discontinued, the infant’s symptoms fully regressed. Specialists from the NPC presented the case at the 13th Spanish Pharmacovigilance Congress held in Oviedo, Spain, in November 2024.

A review of similar cases reported in the Spanish Pharmacovigilance System database identified six additional cases with the same characteristics, all involving infants whose caregivers were using minoxidil. Four more cases were found through the European pharmacovigilance database EudraVigilance and a review of scientific literature, bringing the total to 11 cases.

According to the Navarra Pharmacovigilance Bulletin, these cases are concerning as they highlight the exposure of vulnerable infants to a medication not indicated for their age group. Additionally, the condition can cause significant stress for the families of the affected children.

Mechanism of Transmission Unclear

The exact mechanism by which caregivers transfer minoxidil to infants is not fully understood. In the newly identified cases, specialists suspect the drug was transmitted through direct or indirect contact. Accidental ingestion is also a possibility if the infant’s hands touched treated areas on the caregiver’s skin and were then brought to the mouth.

The NPC explained that infants’ skin is more permeable due to the thinner stratum corneum and a higher surface area/body weight ratio, making them more susceptible to absorbing topically applied medications.

Regulatory Changes and Precautions

In light of these findings, the European Medicines Agency’s Pharmacovigilance Risk Assessment Committee concluded that, starting in October 2024, product information for medications containing minoxidil should be updated. Specifically, new information must be added to the package insert warning about the risk for hypertrichosis in infants following accidental exposure to minoxidil.

The NPC emphasizes the importance of caregivers being aware of the risks associated with topical medications like minoxidil. Recommended precautions include thoroughly washing hands after applying the product and covering treated areas to prevent direct contact with infants’ skin.

Healthcare professionals should also be aware of this risk and consider it when diagnosing hypertrichosis in infants. Recognizing the connection can prevent unnecessary testing for the infant and alleviate stress for the family.

This story was translated fromUnivadis Spain using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.