Alpha-gal syndrome, a tick-borne condition that can lead to a potentially serious allergic reaction to red meat and dairy, has been classified as a public health concern in Massachusetts.
The condition has been identified on Cape Cod, Martha’s Vineyard, and other parts of Massachusetts, according to the Massachusetts Department of Public Health.
Dr. Catherine Brown, an epidemiologist with the state’s Bureau of Infectious Disease and Laboratory Science, said at a recent meeting of the Public Health Council that AGS became a reportable condition in Massachusetts as of April 1, 2026.
AGS develops after a bite from an infected tick, most commonly the lone star tick.
“The sensitization is not immediate. It can take weeks to months to develop after that tick bite,” Brown said.
The condition involves an immune response to the alpha-gal sugar molecule, which is present in most mammalian products, including red meat and dairy items such as milk, cheese, yogurt, and ice cream.
According to Brown, AGS can be identified through a skin allergy test, and is accompanied by allergic or gastrointestinal symptoms that can appear several hours after consuming mammalian products. Some people test positive without experiencing symptoms.
Treatment primarily involves avoiding foods and products derived from mammals. According to the Cleveland Clinic, “some people find they can reintroduce foods containing alpha-gal without symptoms after avoiding them for a year or two.”
“The primary recommendation for treatment is really dietary avoidance of any mammalian products,” she said. “Mild symptoms may be managed with antihistamines, while severe reactions, including anaphylaxis, require epinephrine.“
Reported cases of AGS have increased significantly in recent years. Nationwide, more than 100,000 suspected cases were documented between 2010 and 2022. Since tracking began in Massachusetts earlier this year, 16 confirmed cases have been reported on Cape Cod.
Stephanie Barth, a disease investigator with the Visiting Nurse Association, noted that AGS is expected to become more prevalent on Cape Cod, similar to trends observed on Martha’s Vineyard.
She emphasized that the severity of reactions varies, with some people suffering life-threatening symptoms upon exposure to mammalian products and requiring emergency medication such as epinephrine auto-injectors.
”We have had cases where people were very, very sick. Like if they come in contact with any mammalian meat product, they become very sick — like anaphylaxis,” Barth said.
On Martha’s Vineyard, reported cases have risen sharply from just two confirmed cases five years ago to more than 500 last year.
