October 29, 2026 | Black & Kletz Allergy
Many individuals who are allergic to certain pollen also may experience itching of the mouth, tongue, and/or throat as well as a tingling sensation of the lips after eating certain fresh fruits or vegetables. This occurs due to similarities in the structure of proteins in the pollen and the proteins contained in the fruits or vegetables. Since the proteins are chemically similar, the allergic individual’s body “sees” the proteins in the fresh fruits and vegetables as the protein found in the pollen. As a result, the fresh fruit or vegetable causes an allergic reaction in the sensitive individual usually manifesting itself as itching of the mouth, lips, throat, and/or tongue as opposed to the classic allergic rhinitis (i.e., hay fever) symptoms. This phenomenon is termed pollen food allergy syndrome. In the past it was referred to as oral allergy syndrome.
In pollen food allergy syndrome, as mentioned above, the self-limited symptoms are usually limited to the mouth and throat, and are unlikely to progress to severe allergic reactions such as anaphylaxis. Many of these individuals can usually tolerate cooked vegetables and fruits as the proteins causing this condition are heat labile and will be denatured by the heat. A common example is a cross reactivity that occurs between birch pollen and foods such as pitted fruits (e.g., apples, pears, peaches, nectarines, plums, celery, cherries), kiwis, almonds, hazelnuts, and/or carrots, to name a few.
Pollen food allergy syndrome is also known as a Class 2 food allergy condition. This contrasts with a Class 1 food allergy, in which sensitization occurs primarily through the gastrointestinal tract, but may also occur through the skin and airway. In a Class 1 food allergy, the symptoms may result in life-threatening anaphylaxis.
Cooking the fresh fruits and/or vegetables when possible and avoiding them will minimize the symptoms of pollen food allergy syndrome. Desensitization to certain pollen by means of allergy shots (i.e., allergy immunotherapy, allergy desensitization, allergy hyposensitization, allergy injections) may help some patients enjoy certain fresh fruits and/or vegetables that previously triggered these unwanted oral symptoms.
A similar phenomenon occurs with house dust mite allergy and sensitivity to crustaceans. This is referred to as mite shrimp allergy syndrome. In order to understand this condition, one must first understand the science behind this disorder. In muscles, tropomyosin is an actin-binding protein that binds along actin filaments in muscles and helps regulate muscle contraction and the organization of the cell’s internal skeleton. Its main role outside muscles is to regulate and stabilize actin filaments, which are part of the cell’s cytoskeleton. Actin is a protein that forms thin filaments inside cells and helps them move, maintain their shape, and contract. The tropomyosin in invertebrates is different than the tropomyosin in vertebrates. Vertebrate and invertebrate tropomyosins share a conserved structure and a fundamental role in regulating actin filaments. They differ however in their genes, isoforms, molecular properties, and some aspects of muscle regulation. The tropomyosin in invertebrates is a pan-allergen that is heat stable and implicated in the cross-reactivity among crustaceans, mollusks, house dust mites, and cockroaches because of its high amino acid sequence homology. In contrast, the tropomyosin in vertebrates are considered non-allergenic since they share a high degree of sequence similarity with human tropomyosin. This similarity is thought to help explain why they generally do not trigger the same IgE-mediated allergic responses as invertebrate tropomyosins.
In mite shrimp allergy syndrome, there is a cross-reactivity between house dust mites and shrimp. The allergens in house dust mites are a leading sensitizer for shrimp allergy. In addition, since the inhalation of dust mites, which is a very common occurrence, is known to sensitize susceptible individuals to dust mites, a vegetarian who has never eaten shrimp may be sensitive to shrimp by just being exposed to dust mites.
It should be noted that there is a subgroup of shrimp-allergic individuals who may only present with mouth and throat symptoms due to inhalant tropomyosin sensitization and are not at risk of anaphylaxis. It has been hypothesized that inhaling tropomyosin from house dust mites causes primary sensitization to shrimp, followed by allergic reactions upon shrimp ingestion. However, primary sensitization to heat-labile proteins may also result in mild and self-limited symptoms, as in pollen food allergy syndrome.
Some studies have demonstrated that immunotherapy with dust mite allergens may induce tolerance to shrimp in some shrimp-allergic individuals, similar to how some individuals may develop tolerance to certain fresh fruits and/or vegetables when undergoing allergy shots to certain cross-reacting pollen.
The board certified allergy specialists at Black & Kletz Allergy have been diagnosing and treating mite shrimp allergy syndrome and other food allergies for more than 50 years. We treat both adult and pediatric patients. Black & Kletz Allergy has offices in Washington, DC, McLean, VA (Tysons Corner, VA), and Manassas, VA. All 3 of our locations have on-site parking. For further convenience, our Washington, DC and McLean, VA offices are Metro accessible. Our McLean office location offers a complementary shuttle that runs between our office and the Spring Hill metro station on the silver line. For an appointment, please call our office or alternatively, you can click Request an Appointment, and we will respond within 24 hours by the next business day. If you suffer from any food allergy or food sensitivity as well as other allergic conditions such as allergic rhinitis (i.e., hay fever), asthma, hives (i.e., urticaria), generalized itching (i.e., pruritus), swelling episodes (i.e., angioedema), eczema (i.e., atopic dermatitis), insect sting allergies, medication allergies, eosinophilic esophagitis, mast cell activation syndrome, or immune disorders, we are here to help alleviate these unwelcome symptoms that have been so troublesome, so that you can enjoy a better quality of life. Black & Kletz Allergy is dedicated to providing the highest quality allergy care in a friendly, compassionate, and professional environment.
