A mushroom allergy, like many food allergies, occurs when the immune system reacts to a "trigger" -- in the case of mushroom allergies, the trigger is mushroom-containing food products. The first time a person eats mushrooms, she may not be aware of an allergy. However, her immune system is being "primed" to respond as though mushrooms are harmful to the body. This first exposure is remembered by the immune system, and any subsequent exposures to mushrooms may result in the allergic response, with several characteristic symptoms.
Hives
Medline Plus, a National Institutes of Health website, says that patients with food allergies often experience symptoms within a few hours of ingesting the food to which they are allergic. A person with mushroom allergies may find, for instance, that within two hours of eating mushrooms, she feels itchy and notices the development of hives on her body. Hives are raised red bumps on the body; they occur because the body releases histamine as part of the allergic response. Sometimes hives appear and then disappear quickly, only to appear on other parts of the body. Alternatively, patients may notice that individual hives seem to merge together to form one large area of redness. Mild hives may not need any sort of treatment, while patients with more serious cases may benefit from taking an antihistamine such as diphenhydramine.
Abdominal Symptoms
The itchy discomfort of hives is not the only indication that an allergic reaction is occurring. Medline Plus says that some people with mushroom allergies may feel nauseated and may vomit. Others may experience unpleasant stomach cramps or diarrhea. Still other patients may react to a mushroom exposure with complaints of abdominal pain. These are all possible symptoms of an allergic reaction and reflect the complicated immune response that is triggered when a person is exposed to an allergen.
Anaphylaxis
In severe cases of mushroom or other food allergies, the patient may suffer an especially serious allergic reaction called an anaphylactic response. According to Dr. Estelle Simons and Dr. Carlos Camargo Junior, writing in the medical reference UpToDate, symptoms indicating that a patient is experiencing an anaphylactic response include swelling around the mouth, tongue swelling or lip swelling; difficulty breathing or swallowing; fainting or a sudden loss of consciousness; and even incontinence. A person with mushroom allergies who notices any of these symptoms should not hesitate to go the emergency room. An anaphylactic response can quickly cause organ failure and may even be fatal. Patients with a known history of an anaphylactic response to mushrooms should carry an "Epi-Pen" -- a pen-like, portable container of the injectable medication epinephrine -- in case they are inadvertently exposed to this life-threatening food allergen.
References
- Medline Plus: Food Allergy
- Medline Plus: Hives
- "UpToDate"; Pathophysiology of Anaphylaxis; S. Kemp; June 2010
- "UpToDate"; Anaphylaxis: Rapid Recognition and Treatment; F. Estelle R. Simons and C. Camargo Jr.; June 2010
