Jaida Moon, a 43-year-old former medical assistant from Portland, Oregon, grew up with several allergies and a strong aversion to mushroom as a kid.
Mushrooms are eaten extensively for their taste and the nutrients they provide, but some people are allergic to them. Although several species of edible mushrooms are safe for the average consumer, they can trigger allergic reactions among some people.
When Moon was 20, she suffered a severe allergic reaction after consuming many servings of a dish that included mushrooms. “Within 20 minutes, I started to feel strange, and got extremely itchy,” she says. “The rash from my abdomen had spread to my arms and legs. Even my lips and tongue were swelling up fast. When my throat felt very tight and I found it hard to breathe, my dad took me to the emergency room, where I was diagnosed with anaphylaxis due to ingestion of mushrooms.
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“Since then, I have been careful enough to avoid them, and I have always carried an EpiPen (an injection containing epinephrine which is used in life-threatening allergic reactions) with me in case of another such attack. I have had brief exposures through juice and skin creams, which were controlled using substantial amounts of antihistamines as per doctors’ supervision.”
According to an article published in the Journal of Allergy and Clinical Immunology in 2020, allergic reactions to mushrooms can occur through ingestion, inhalation and contact. The characteristics of mushroom allergens are poorly understood, and it is yet unknown whether the spores, cap and stalks contain similar or unique allergens.
An allergy occurring through ingestion is a type of food allergy. “The immune cells overreact to the proteins of the mushroom,” says Dr Vyakarnam Nageshwar, who is the director and chief consultant of allergy and immunology at Aswini Allergy Centre, Hyderabad. “Many people think that this is an immune system dysfunction. It is just the effective immune system that decides how much it should react to the mushroom protein inside your body.”
Types of mushroom allergies
“There are eight to ten varieties of mushrooms, and distinct types trigger different reactions,” Dr Akash Shah, a consultant pathologist at Neuberg Supratech Reference Laboratories, Ahmedabad, tells Happiest Health. “There are two types of mushroom allergies: one is caused through ingestion and the other through inhalation of spores. Allergy caused by ingestion is quite rare and less severe as compared with the one caused by inhalation. Since the use of mushroom has increased in the consumer market, the number of cases of reactions to mushrooms has also increased.”
Typical symptoms of mushroom allergies
Symptoms depend on where the allergic reaction takes place in the body, says Dr Nageshwar. The following symptoms are seen depending on the part of the body where allergic reaction occurs:
- Abdomen: abdominal cramps, nausea, vomiting
- Skin: severe rashes, hives
- Respiratory passages: bronchospasm, dry cough, breathlessness
- Eyes: reddening and itching of the eyes
- Nose: running nose, stuffiness, heaviness in the head.
“If immune hyperreactivity is not controlled immediately, it can further aggravate the airways — causing obstruction of oxygen supply and leading to an anaphylactic shock, which is a life-threatening condition,” says Dr Nageshwar.
Diagnosis
“Modified allergen prick skin test is recommended as it shows how much of mushroom content can trigger a reaction,” says Dr Nageshwar. “This gives larger scope to an individual to realise how the body will react when one consumes mushrooms.”
Dr Shah says two types of investigations can be done in the case of mushrooms. “One is ImmunoCAP allergy test, which is the gold standard for allergy testing,” he says. “But the disadvantage is that it can only detect a single mushroom-type allergen. It might miss potential mushroom allergens. Another type is the microarray testing, which ensures the right diagnosis.
“Since mushroom is mixed in several dishes, it can be tricky to know if you are allergic. Still, it is easily diagnosable when compared to the allergy caused by inhalation. It is only through testing that a mushroom allergy can be confirmed.”
How certain ingredients flare up the mushroom allergy
“Cultivated mushrooms are not eaten raw,” says Dr Nageshwar. “They are cooked with other ingredients. What people do not realise is that the mixture of spices, garlic and ginger has high histamine content. Besides histamine release by the immune system in an allergic person, these ingredients dump more histamine into your body, leading to uncontrolled hyperreactivity, causing anaphylaxis.”
Prevention
“The first step would obviously be to avoid it,” says Dr Nageshwar. “Since mushrooms have entered the consumer market in various products, people should be vigilant enough to look out for mushrooms in different products.”
Treatment
“The first line of defence to any kind of allergy is antihistamine treatment for mild cases,” says Dr Shah. “In severe cases, the patient might need to be hospitalised for further treatment and investigation. Doctors advise people who are severely allergic to carry an EpiPen, which contains epinephrine and is a life-saving drug in such cases.
“There are allergy-desensitisation treatments available as well that attempt to treat the cause of the allergy rather than the symptoms.”
