Developing a new sensitivity to a food you have eaten for years can be a confusing experience. If you are wondering if you can develop an allergy to strawberries later in life, the answer is yes. A food allergy is defined by an immune system overreaction where the body mistakenly identifies a protein in the food as a threat. This triggers the production of specific antibodies and the release of chemicals, such as histamine, causing various physical symptoms.
The Reality of Adult-Onset Strawberry Allergy
Food allergies are not static conditions limited to childhood. Nearly half of adults living with a food allergy in the United States developed it after the age of 18. This phenomenon, known as adult-onset food allergy, can happen even with foods previously consumed without issue.
Changes in the immune response can be triggered by various factors, including hormonal shifts, especially in women during life stages like pregnancy or menopause. New environmental exposures or a viral or bacterial infection can sometimes sensitize the immune system to a food protein. These changes mean the body begins to recognize a harmless food protein as an allergen, leading to a reaction upon subsequent exposure.
Understanding the Causes: True Allergy vs. Cross-Reactivity
When reacting to strawberries, adults often experience one of two distinct categories: a true immunoglobulin E (IgE)-mediated allergy or Oral Allergy Syndrome (OAS). A true IgE-mediated strawberry allergy involves the immune system directly targeting specific strawberry proteins, notably Fra a 1. This reaction is generally more severe and can occur with both raw and cooked strawberries.
The more common cause of strawberry sensitivity in adults is Oral Allergy Syndrome (OAS), also known as pollen-food allergy syndrome. OAS is a form of cross-reactivity where the immune system, already sensitized to an environmental allergen like birch pollen, mistakes similar-shaped proteins in raw fruits for the pollen. Strawberries contain proteins that closely resemble those found in birch pollen, triggering a localized allergic response.
In OAS cases, the reaction is typically confined to the mouth and throat because the allergenic proteins are easily broken down by stomach acid or heat. This is why many people with OAS can safely consume cooked strawberries in jams or baked goods, but react to the fresh fruit. Since OAS is linked to seasonal allergies, the symptoms may also be more noticeable during peak pollen seasons.
Recognizing the Symptoms and Severity Levels
Strawberry reactions range widely in presentation and severity, depending on whether the cause is a true allergy or OAS. Symptoms of Oral Allergy Syndrome are usually mild, including itching, tingling, or slight swelling of the lips, mouth, tongue, or throat shortly after eating the fresh fruit. These symptoms are localized and typically disappear within minutes of swallowing the food.
A true IgE-mediated allergy can affect multiple organ systems and cause severe reactions. These symptoms may include hives, widespread rash, or swelling of the face, tongue, or throat. Gastrointestinal issues like vomiting, abdominal pain, or diarrhea are common signs of a systemic reaction.
The most serious reaction is anaphylaxis, which is life-threatening and requires immediate emergency medical attention. Signs of anaphylaxis include difficulty breathing, wheezing, a sudden drop in blood pressure causing dizziness or fainting, and throat tightness. If any of these severe symptoms occur, an epinephrine auto-injector must be administered right away.
Diagnosis and Management Strategies
If you suspect you have developed a strawberry allergy, the first step is to consult an allergist for an accurate diagnosis. Diagnosis typically begins with a detailed review of your medical history and specific reactions, followed by testing. Skin prick tests involve placing a small amount of strawberry extract on the skin and lightly pricking the surface to observe for a reaction.
An allergist may also order a blood test to measure the level of IgE antibodies specific to strawberry proteins. In some cases, an oral food challenge, where the food is consumed in increasing amounts under medical supervision, may be necessary to confirm the diagnosis. Once confirmed, the primary management strategy is strict avoidance of strawberries and any products containing them.
It is important to read ingredient labels carefully, as strawberries can be hidden in flavored yogurts, candies, and certain beverages. For individuals diagnosed with a severe allergy, carrying an epinephrine auto-injector is a necessary precaution for accidental exposure. Antihistamines can help alleviate mild symptoms, but they are not a substitute for epinephrine during a severe allergic reaction.