Mushroom Allergy & Intolerance: Symptoms, Signs and Testing

Mushrooms are a popular ingredient in countless dishes, from creamy pastas to stir-fries, risottos, soups, and plant-based meals. Some people swear by their unique taste, while others aren’t the biggest fans of their texture. They’re nutrient-rich, low in calories, and widely considered a healthy addition to most diets. But for some people, mushrooms can trigger uncomfortable or even serious reactions.

Both mushroom allergy and mushroom intolerance are becoming more widely recognised, particularly as people pay closer attention to how foods affect their digestion, skin, and energy levels. Symptoms can range from mild discomfort to more severe allergic responses, depending on the individual and the type of mushroom involved.

If you suspect mushrooms may be causing unwanted symptoms, this guide explains what to look for, how reactions differ, and how to find clarity through testing.

Symptoms of Mushroom Allergy

A mushroom allergy occurs when the immune system mistakenly identifies proteins in mushrooms as harmful, triggering an allergic response. Symptoms may appear within minutes to a couple of hours after eating mushrooms or, in rare cases, after touching them.

Common mushroom allergy symptoms include:

Mild to Moderate Symptoms

• Itching, tingling, or swelling of the lips, mouth, or throat
• Hives, rashes, or skin irritation
• Sneezing, runny nose, nasal congestion
• Itchy or watery eyes
• Nausea, stomach discomfort, or vomiting

Potentially Severe Symptoms

• Swelling of the face, tongue, or airway (a risk in oral allergy syndrome)
• Coughing, wheezing, or difficulty breathing
• Severe abdominal pain or diarrhoea
• Anaphylaxis (rare but can happen)

Some people experience reactions to specific mushroom varieties. For example, shiitake mushroom allergy can cause a unique rash known as shiitake dermatitis, which appears as red, linear streaks on the skin. If symptoms escalate quickly or breathing becomes difficult, call emergency services as soon as possible.

Symptoms of Mushroom Intolerance

Contrary to what many believe, a mushroom intolerance is different from an allergy. It does not involve the immune system and is usually caused by the body struggling to break down certain compounds in mushrooms (such as chitin or FODMAPs). Overall, mushroom intolerance symptoms are less severe than mushroom allergy symptoms, but they can still be very disconcerting. 

These symptoms are typically delayed and often digestive in nature.

Common symptoms of mushroom intolerance include:

• Gas, bloating, or excessive wind
• Abdominal discomfort or cramping
• Diarrhoea or loose stools
• Nausea after eating mushrooms
• Fatigue or sluggishness
• Headaches or brain fog

Many people report mushroom intolerance with stomach pains as one of their main issues, often appearing several hours after eating mushrooms.

Can you develop sudden mushroom intolerance?

In short, yes, some people tolerate mushrooms for years before suddenly developing symptoms. While not overly common, it can occur. This may be linked to changes in gut health, enzyme deficiencies, or increased sensitivity to high-FODMAP foods.

How Common Are Mushroom Allergies and Intolerances?

As with any allergy and intolerance, deciphering exactly how many people are affected can be challenging. After all, many unknowingly suffer and never report their symptoms.  On the whole, mushroom allergies and intolerances are considered uncommon, but they do happen, and they may be underdiagnosed. As awareness of intolerances and allergies becomes more and more prevalent, so too does the number of recorded cases, implying that these conditions are often more common than many realise. 

People who react to moulds or environmental fungi may also be more prone to mushroom reactions due to cross-reactivity.

Varieties of mushrooms most commonly associated with reactions include shiitake, oyster mushrooms, button mushrooms, portobello, and enoki.

How A Mushroom Allergy Can Affect Your Stomach

While allergies often cause immediate symptoms such as itching or swelling, stomach issues can also occur, particularly nausea, vomiting, diarrhoea, or sharp abdominal cramps.

This happens when the allergic reaction affects the gastrointestinal tract. However, stomach symptoms alone are more commonly linked to intolerance rather than allergy.

Foods to Avoid With a Mushroom Allergy or Intolerance

Avoiding mushrooms may sound simple, but they can appear in more dishes than you might expect. Some of the less obvious places they pop up include:

• Pasta sauces
• Gravies and stocks
• Soups
• Stir-fries
• Vegan burgers
• Seasoning blends (e.g. mushroom powder or dried shiitake)
• And certain ready meals

If you have a confirmed allergy, avoiding cross-contamination is also important, especially in restaurants where the risk of cross-contamination is significantly higher.

For intolerance, complete elimination may not be necessary; some people can often tolerate small amounts or specific varieties better than others. However, it’s always important to listen to what your body is telling you, how you react to certain mushrooms, and consult with a medical professional where possible. 

Mushroom Allergy Treatment

Treatment for mushroom allergies depends on the severity of your symptoms.

For Mild Allergic Reactions

• Stop eating the food immediately.
• Take antihistamines to help reduce itching, swelling, or a runny nose.
• Monitor symptoms closely.

For Severe Reactions

Seek urgent medical care.

• Use an adrenaline auto-injector (EpiPen) if prescribed.
• Call emergency services immediately.
• Do not rely on inhalers or antihistamines during anaphylaxis.

If you suspect you have a mushroom allergy, speak with a healthcare professional for personalised advice.

Alternatives to Mushrooms

If you need to avoid mushrooms entirely, several substitutes provide similar texture or umami flavour:

• Aubergine (eggplant)
• Courgette (zucchini)
• Caramelised onions
• Roasted peppers
• Seaweed or miso (for savoury flavour)
• Lentils (in place of mushrooms in plant-based dishes)

When trying any of these alternatives, introduce them gradually and monitor your symptoms. The last thing you want is for your body to think you are consuming a mushroom because of a similar flavour or texture. 

Testing for Mushroom Allergy and Intolerance

If mushrooms seem to trigger symptoms, from digestive discomfort to skin issues or fatigue, testing can help identify the cause.

YorkTest’s premium food intolerance test analyses IgG antibody responses to over 200 ingredients, including mushrooms, helping you understand whether your body is reacting to them.

As part of the test, you’ll receive:

• A simple at-home finger-prick kit
• Scientific analysis in our ISO-accredited laboratory
• Clear, easy-to-read results
• A 30-minute consultation with a nutritional therapist to help you build a personalised plan

Understanding your responses to mushrooms and other foods can be the first step toward better health, more energy, and improved day-to-day well-being.

Take Control of Your Health With YorkTest

Whether you’re experiencing digestive issues, skin flare-ups, or unexplained fatigue after eating mushrooms, identifying your triggers can make all the difference. YorkTest’s range of at-home tests provides clarity and expert support to help you optimise your wellbeing.

Discover whether mushrooms, or other foods, are contributing to your symptoms and take the next step toward feeling your best. Contact us today.