Allergies occur when the body’s immune system overreacts to substances that are typically harmless, known as allergens. These can include pollen, pet dander, and certain foods. When encountered, the immune system mistakenly identifies allergens as a threat, triggering a defensive response that leads to various symptoms.
The Possibility of New Allergies
It is possible to develop new allergies at any point in life, including during adulthood. This phenomenon, often termed adult-onset allergies, is a common occurrence and not limited to childhood. Many adults experience the emergence of allergic reactions to substances they have previously encountered without issue. For instance, approximately 10.8% of adults in the United States report having a food allergy, with nearly half of these individuals developing at least one food allergy later in life. This demonstrates that the immune system can become sensitized to allergens even after years of tolerance.
Factors Contributing to Adult-Onset Allergies
Several factors are believed to play a role in why allergies manifest in adulthood. The immune system undergoes changes as people age, which can make it more responsive to allergens that were once tolerated. New environmental exposures, such as moving to a different geographical region or acquiring a new pet, can introduce novel allergens. Occupational exposures, like working with new chemicals or materials, may also contribute.
Hormonal fluctuations, with events like pregnancy or menopause, can influence immune sensitivity. The “hygiene hypothesis” suggests that reduced exposure to certain microbes in childhood might contribute to immune system imbalances. Childhood antibiotic use has also been linked to allergy development. A genetic predisposition can increase the likelihood of developing allergies, even if they do not appear until adulthood. Repeated or cumulative exposure to an allergen over time can also eventually lead to a reaction.
Identifying New Allergy Symptoms
Common indicators of new allergies often involve the skin, respiratory system, or digestive tract. Skin reactions may include hives, eczema, or generalized itchiness. Respiratory symptoms can manifest as sneezing, a stuffy or runny nose, coughing, wheezing, or itchy, watery eyes. Digestive issues like stomach cramps, nausea, or diarrhea might signal a food allergy.
Adults can develop allergies to a wide range of substances. Common food allergens that emerge in adulthood include shellfish, peanuts, tree nuts, and finned fish. Some individuals may experience oral allergy syndrome, where proteins in certain raw fruits or vegetables cause itching or tingling in the mouth, often linked to pollen allergies. Environmental triggers such as pollen, dust mites, pet dander, and mold are also frequently responsible for new adult-onset allergies. Additionally, reactions to medications, insect stings, or latex can appear for the first time in adulthood.
In severe cases, a life-threatening reaction called anaphylaxis can occur. Symptoms may include widespread hives, swelling of the face, mouth, throat, or tongue, difficulty breathing, wheezing, a rapid heart rate, clammy skin, anxiety, dizziness, vomiting, or fainting. Immediate medical attention is necessary.
Diagnosis and Management of Adult Allergies
If new or persistent symptoms suggest an allergy, consulting a healthcare professional, especially an allergist, is important. The diagnostic process typically begins with a detailed review of personal and medical history, including symptoms and potential exposures, and a physical examination. Keeping a diary of symptoms and possible triggers can provide valuable information.
To identify specific allergens, healthcare providers may use various tests. Skin prick tests involve placing small amounts of allergen extracts on the skin and observing for a localized reaction. Blood tests, specifically allergen-specific IgE tests, measure the levels of certain antibodies in the blood. For suspected food allergies, an elimination diet might be recommended.
Managing adult-onset allergies often involves a multi-faceted approach. Avoiding known allergens is a fundamental strategy to prevent reactions. Medications such as antihistamines can help alleviate symptoms like itching and sneezing by blocking histamine, a chemical released during allergic reactions. Decongestants can reduce nasal congestion, while intranasal corticosteroids and eye drops may be prescribed for specific respiratory or eye symptoms. For long-term management and desensitization, immunotherapy, delivered through allergy shots or sublingual tablets, can be an option. Individuals at risk for severe reactions are often advised to carry an epinephrine auto-injector for emergency use.