Hair loss occurred for some patients within months of developing the swine flu, according to a new report published in the Journal of Dermatology.

Alopecia areata, a condition in which patches of hair fall out, has been linked to patients with swine flu (H1N1), according to researchers in Japan. The condition is believed to occur when the immune system attacks the hair follicles. Although some are genetically predisposed to develop the condition, an environmental stress may also be needed to set the condition in motion.

It’s very plausible that the flu could trigger hair loss, said Nanette Silverberg, director of pediatric and adolescent dermatology at St. Luke’s-Roosevelt Hospital Center in New York, who was not involved in the study.

In the study, between 2009 and 2010, seven patients were examined with hair loss following an H1N1 infection. For four of them, the hair loss was an existing condition and for three it was a new condition. Four of the patients were under the age of 10 and three were female.