It is possible to develop allergies later in life, even to substances you have previously tolerated without issue. These adult-onset allergies can emerge at any age, often appearing in a person’s twenties or thirties. Allergies involve an immune system reaction to a normally harmless substance, which the body mistakenly identifies as a threat. This can lead to symptoms ranging from mild discomfort to severe, potentially life-threatening reactions.
Understanding Adult-Onset Allergies
The immune system is central to allergy development. It recognizes certain substances as allergens and produces immunoglobulin E (IgE) antibodies in response. Upon subsequent exposure, these antibodies trigger the release of chemicals like histamine, leading to allergic symptoms.
While the exact reasons for adult-onset allergies are not fully understood, several factors are believed to contribute. Environmental changes can introduce new allergens, such as moving to an area with different pollen or acquiring a new pet. Hormonal shifts, like those during pregnancy or menopause, can also influence immune function. A weakened immune system due to illness or stress may also alter the body’s response to substances, increasing allergy likelihood.
Common Types of Adult-Onset Allergies
Adults can develop new sensitivities to various allergens, including foods, environmental factors, and medications. Food allergies are common, with shellfish, tree nuts, and fish frequently reported as triggers. For example, a person might develop an allergy to shrimp after years of consumption. Oral allergy syndrome, also known as pollen-food syndrome, can also appear in adulthood, causing symptoms like an itchy mouth or throat after eating raw fruits and vegetables due to cross-reactivity with pollen.
Environmental allergies, such as seasonal allergies to pollen, mold spores, dust mites, and pet dander, can also develop or worsen. These may present as sneezing, nasal congestion, or itchy, watery eyes. Medication allergies, including those to antibiotics like penicillin, pain relievers such as aspirin or ibuprofen, and sulfa drugs, can also emerge. New or increased exposure to these medications can trigger an allergic response.
Identifying and Managing New Allergies
Recognizing symptoms is key to managing a new allergy. Common indicators include skin reactions like hives, itchy rashes, or eczema. Respiratory issues such as coughing, wheezing, shortness of breath, or nasal congestion may also occur. Digestive problems like nausea, vomiting, abdominal pain, or diarrhea are often associated with food allergies. In severe cases, an allergic reaction can escalate to anaphylaxis, a life-threatening condition characterized by difficulty breathing, a sudden drop in blood pressure, and dizziness.
If a new allergy is suspected, consult an allergist for diagnosis. Diagnosis involves a detailed medical history, a physical exam, and specific allergy tests. Skin prick tests, where small amounts of potential allergens are applied to the skin to observe for a reaction, are common. Blood tests measure IgE antibodies in response to specific allergens.
Management strategies involve avoiding known allergens, using over-the-counter or prescription medications like antihistamines and nasal sprays to alleviate symptoms, and sometimes immunotherapy (allergy shots) to desensitize the immune system. Individuals at risk of severe reactions should carry an epinephrine auto-injector as part of an emergency plan.
Clarifying Allergy Versus Intolerance
Allergies and intolerances are often confused, but they involve distinct bodily mechanisms and have different implications. An allergy is an immune system response where the body mistakenly identifies a harmless substance as a threat, producing IgE antibodies. This immune reaction can be severe and potentially life-threatening, even with minimal exposure to the allergen. Symptoms often appear rapidly, within minutes to a few hours of exposure.
Conversely, an intolerance does not involve the immune system. Instead, it arises from the body’s inability to properly digest or metabolize a food component, often due to a lack of a specific enzyme. For example, lactose intolerance occurs when the body lacks sufficient lactase, the enzyme needed to break down lactose in dairy products. Intolerance symptoms are less severe than allergies, often affecting the digestive system, and appear more gradually, sometimes hours after consumption. A person with an intolerance may consume small amounts of the problematic food without symptoms, which is not typically the case with a true allergy.