Allergy Testing

Overview

Allergy testing is a medical evaluation that helps find out whether your immune system overreacts to harmless substances such as pollen, dust mites, pet dander, or certain foods. It can help you and your doctor understand what may be causing symptoms like sneezing, itching, or hives.

Allergy testing is a common procedure offered in many general practices and allergy clinics. Allergies themselves affect millions of people worldwide.

Anyone with suspected allergies may be offered testing, including children, adults, and older people. It is most often considered when symptoms keep returning or interfere with daily life.

Symptoms

Common symptoms

• Sneezing or a runny or blocked nose
• Itchy, watery, or swollen eyes
• Itching, hives, or eczema
• Coughing, wheezing, or shortness of breath
• Stomach pain, nausea, or diarrhea after eating certain foods

Symptoms in children

• Eczema that flares up in certain situations
• Repeated cold-like symptoms or ear infections
• Trouble with certain foods – such as itching in the mouth or stomach upset

Symptoms in older adults

• New or worsening sneezing and nasal congestion
• Skin rashes or itching that come and go
• Wheezing or breathlessness that is not better explained by other conditions

Causes

Main causes

• Your immune system mistakenly reacts to a harmless substance (an allergen) as if it were a threat
• The body releases a chemical called histamine, which causes allergy symptoms
• The exact reason this happens is not always clear – genetics and environment both play a part

Risk factors

• A family history of allergies or asthma
• Having asthma or a skin condition like eczema
• Exposure to certain allergens at home, school, or work
• A childhood history of food allergies or eczema

When to see a doctor

See a doctor urgently if:

• If you have sudden trouble breathing, swelling of your face or throat, or feel faint – call your local emergency number immediately
• If you have a severe allergic reaction (anaphylaxis), call for emergency help right away

Book a routine appointment if:

• If you have bothersome symptoms such as sneezing, itching, or stomach upset that do not improve with self-care
• If you suspect a particular food or substance is causing your symptoms, keep a symptom diary and discuss it with your doctor
• If you have had an allergic reaction before and want to know what triggered it

Diagnosis

Your doctor will first ask about your symptoms, your home and work environment, and your family history. If they think an allergy is likely, they may suggest allergy testing.

Tests that may be done

• Skin prick test – a small drop of allergen is placed on your skin and the skin is lightly pricked; a small raised bump may appear if you are allergic
• Blood test – measures allergy-related antibodies in a sample of blood
• Patch test – allergen patches are placed on your skin for a day or two, mainly for contact allergies

What to expect at your appointment

Before a skin test, you may be asked to stop taking some allergy medicines for a few days. The test itself takes about 30–60 minutes. Your doctor or nurse will explain the results and what they mean for you.

Treatment

Finding out what you are allergic to is the first step. Avoiding the trigger is the most effective way to prevent symptoms. There are also treatments to help control symptoms when they happen.

Self-care at home

• Avoid known triggers where possible – for example, using dust mite covers or staying indoors when pollen counts are high
• Keep a symptoms diary to notice patterns
• Use salt-water nasal rinses or a cold compress for mild nasal or eye symptoms
• If you have food allergies, always read ingredient labels and tell restaurants about your allergy

Medical treatments

Your doctor may suggest over-the-counter or prescription medicines to help manage symptoms. These can include antihistamines, nasal sprays, or eye drops. For some people, allergy immunotherapy – also called desensitization – may be an option. This treatment slowly exposes the body to the allergen over time. Always talk to your doctor about which treatment is right for you.

When is surgery considered?

Surgery is not a treatment for allergies, but in rare cases surgery may be considered for problems linked to allergies, such as nasal polyps or chronic sinusitis. This is not common and your specialist will discuss it with you if needed.

Living with this condition

Living with allergies often means planning ahead. Knowing your triggers and having a simple action plan can help you avoid uncomfortable symptoms and enjoy your daily life.

Lifestyle tips

• Keep windows closed on high-pollen days and use a good filter or vacuum
• Wash bedding in hot water regularly to reduce dust mites
• If you have a pet allergy, keep animals out of the bedroom and wash your hands after touching them
• Carry an allergy action card or medical ID if you have a food allergy or have had a severe reaction

Diet and exercise

For food allergies, the best approach is to avoid the specific food. Work with your doctor or dietitian to make sure your diet stays balanced. Exercise is safe and encouraged – just be aware that in rare cases, some people have symptoms when allergic to food and exercise together.

Mental health and emotional wellbeing

Living with allergies can be stressful, especially if symptoms are severe or you worry about accidental exposure. It is normal to feel anxious. Talk to your doctor if these feelings are affecting your life, and remember you are not alone.

Prevention

You cannot always prevent allergies from developing, but you can prevent symptoms by avoiding known triggers. Testing helps you identify which triggers matter for you.

Vaccines

There is no vaccine to prevent allergies, but allergy immunotherapy (sometimes called 'allergy shots') is a treatment that can reduce sensitivity over time.

Screening programmes

Screening for allergies is not routinely done without symptoms. Testing is done when a person has symptoms and a possible trigger.

Complications

If left untreated

• Untreated allergic rhinitis (hay fever) can lead to sleep problems and poor concentration
• Untreated food allergies carry a risk of severe reactions if you accidentally eat the allergen
• Long-standing eczema or asthma may get worse if trigger allergens are not identified and avoided

Long-term outlook

The outlook for people with allergies is good. Most people can manage their symptoms well with avoidance, medicines, and support. For those with severe allergies, there are safe and effective plans to reduce risk and stay well.

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