Allergies are a prevalent health concern affecting millions of people worldwide. 

And while we often associate them with children, adult-onset allergies can be particularly challenging. 

It is possible to live without issues for decades before symptoms emerge. 

This article offers some general information. If you feel you have developed an allergy or have any other health concerns, contact your general practitioner or other health professional. 

Pollen: Seasonal allergies, or hay fever, caused by pollen from trees, grasses, and weeds can develop at any age. Symptoms include sneezing, runny or stuffy nose, itchy eyes, and throat irritation. 

Dust mites: These microscopic organisms thrive in household dust. Symptoms of dust mite allergies include sneezing, runny nose, itchy eyes, and asthma-like symptoms such as wheezing and difficulty breathing. 

Mould: Exposure to mold spores can lead to allergic reactions, particularly in damp environments. Symptoms may include nasal congestion, coughing, wheezing, and skin irritation. 

While food allergies are often associated with childhood, they can also develop in adults. Some common adult-onset food allergies include: 

Shellfish: Shrimp, crab, lobster, and other shellfish are common allergens. Symptoms range from mild hives and itching to severe anaphylaxis. 

Nuts: Peanuts and tree nuts, such as almonds, walnuts, and cashews, can cause allergic reactions. Symptoms include hives, swelling, abdominal pain, and anaphylaxis. 

Dairy: Although lactose intolerance is more common, some adults may develop an allergy to the proteins in cow's milk, leading to hives, digestive issues, and respiratory symptoms. 

Allergic reactions to medications can occur at any age, often unexpectedly. 

Antibiotics: Penicillin and related antibiotics are common culprits. Reactions can range from mild rashes to severe anaphylaxis, which can be life-threatening. 

Nonsteroidal anti-inflammatory drugs: Medications such as ibuprofen and aspirin can cause allergic reactions, including hives, swelling, and anaphylaxis. 

Anticonvulsants: Used to treat epilepsy and other conditions, these medications can cause severe skin reactions and other allergic responses. 

Reactions to insect stings can develop later in life, even if previous stings caused no issues: 

Bees and wasps: Stings can cause local swelling, redness, and pain. In some cases, they trigger systemic reactions, including anaphylaxis. 

Fire ants: Stings can lead to intense pain, itching, swelling, and severe allergic reactions. 

Latex, found in many medical and household products, can cause allergic reactions. 

Symptoms include skin rashes, itching, respiratory problems, and in severe cases, anaphylaxis. Healthcare workers and others with frequent latex exposure are at higher risk. 

The exact reasons why allergies develop later in life are not entirely understood, but several factors may contribute: 

Environmental changes: Moving to a new area with different allergens can trigger reactions. 

Immune system changes: Ageing or underlying health conditions can alter immune system function, making it more susceptible to new allergens. 

Increased exposure: Repeated exposure to an allergen over time can eventually lead to sensitisation and allergic reactions. 

Hormonal changes: Hormonal fluctuations, particularly during pregnancy or menopause, can influence the immune system and lead to allergies.