Beyond allergy season: What to know about histamine and related conditions
Fall allergy season is underway in Georgia, with ragweed pollen triggering symptoms such as sneezing, a runny nose and itchy eyes. Histamine plays a key role in these reactions, but its effects on the body go beyond seasonal allergies.
Two other conditions that have gained attention online, mast cell activation syndrome (MCAS) and histamine intolerance, involve different processes and can cause symptoms that overlap with those of allergies.
What is histamine?
Histamine acts as a chemical messenger, said Dr. Lily Hwang, board-certified allergist and immunologist, and chief medical officer of Atlanta Allergy & Asthma.
“They’re a bioamine chemical that goes through your immune system,” Hwang said. “They are stored in cells called mast cells, which can be found in the skin, airways, and gut. When triggered, the mast cells release histamine — cue the sneezing, stuffy nose, and itching.”
While the side effects of a histamine release can be irritating, Hwang notes that histamine plays a critical part in your body.
“Histamines are protective. They get triggered when there’s an infection. It’s part of your body’s defense system,” she said.
While most people lean on over-the-counter antihistamines that help relieve symptoms, other histamine-related conditions are gaining attention, particularly on social media.
Histamine intolerance and MCAS
Although histamine intolerance and MCAS can cause similar symptoms, they are distinct conditions.
“The core difference is where the histamine comes from,” Hwang said.
MCAS occurs when mast cells release too many chemical mediators, including histamine, potentially triggering symptoms and inflammation that can affect multiple parts of the body.
Histamine intolerance is when histamine from food overwhelms the body’s ability to break it down, Hwang explained. It’s triggered by histamine-rich foods, such as fermented foods, aged cheese and meat.
A food’s histamine content doesn’t tell the whole story. Some people with pollen allergies experience reactions because proteins in those foods resemble proteins in pollen. Known as oral allergy syndrome, this cross-reaction can cause symptoms such as itching or tingling in the mouth.
“Oral allergy syndrome is why people can’t tolerate fresh fruits and vegetables, because they are structurally similar allergens to trees, grass, and weeds,” said Hwang. “You could have a cross-reaction, and if you don’t talk to a board-certified allergist, you might not know.”
Supplements or natural remedies can also trigger reactions in some people. For example, chamomile tea is often promoted online as a way to improve gut health and, in turn, allergies. But chamomile belongs to the same plant family as ragweed, and people with ragweed allergies may react to it.
When should you seek help?
Whether you’re dealing with seasonal allergies or symptoms you suspect may be related to histamine, Hwang encourages people not to wait years to seek answers.
She said many of her patients come to her after struggling with symptoms for years or even decades. She recommends seeing a board-certified allergist if symptoms aren’t well-managed with a reasonable dose of an over-the-counter antihistamine.
Hwang also cautions against turning to quick fixes found online, such as supplements and restrictive diets.
“Before we step into life-changing modalities, I recommend you try to sort out what’s truly going on,” she said.
She also cautions against low histamine diets, which can unnecessarily restrict what people eat without addressing the underlying cause of their symptoms.
“These diets can be nutritionally depleting and frustrating… and you don’t always know the reason for the symptoms you’re trying to treat,” Hwang said.
Rather than eliminating foods on their own, she recommends working with an allergist to identify potential trigger foods and determine whether dietary changes are necessary.
Hwang knows how frustrating allergies and allergic reactions can be, especially for people who have spent years managing symptoms without answers.
“It’s a journey for every single patient that comes in because they’ve gone through so much,” she said.
For people who suspect histamine may be contributing to their symptoms, a board-certified allergist can help identify the underlying cause and determine an appropriate treatment plan.
“We can give patients a significant improvement in the quality of life,” Hwang said.