Test / Diagnostic Procedure: Allergy Testing London

Around 41 million people in the UK live with allergies of some kind. At OneWelbeck, our wide range of allergy tests provide peace of mind and help you take charge of your health.

To book offline, call our Skin Health and Allergy centre directly on: 02036532007

Enquiries: bookings.skinhealthallergy@onewelbeck.com

What is allergy testing?

Allergies are a common problem that anyone can have at any age.

It’s when your body’s immune system reacts to something, such as food, pollen, medication or chemicals and mistakes it for something harmful. Allergies can be mild, but they can also be severe and rarely cause anaphylaxis. Anaphylaxis is a life-threatening allergic reaction. It is a medical emergency and requires immediate treatment.

Allergy testing can help you understand your allergy and how it may affect your body. The correct allergy test for you will depend on your type of allergy.

Why might I need private allergy testing?

Allergy tests may confirm the cause of your symptoms.

Once a diagnosis has been made, the correct management plan can be put in place.

What symptoms might be related to an underlying Allergy?

Airborne allergy (allergies to pollen, hay fever, dust mites or pet dander) symptoms include: 

  • A runny nose

  • Sneezing

  • Itchy eyes

  • Scratch throat

  • Coughing

  • Wheezing

Food allergy symptoms may include: 

  • Itchy mouth

  • Swelling of the lips, tongue and throat

  • Raised, itchy rash

  • Nausea

  • Vomiting

  • Anaphylaxis (in severe cases)

A drug allergy (reaction to medication) can cause symptoms such as; 

  • Swollen face, eyes, lips, tongue and throat

  • Rashes


Allergy symptoms can occur very quickly after contact with an allergen or develop up to several hours afterwards. In response to a chemical allergy (eg chemicals in a cosmetic product) it can take several days to appear as ‘eczema”

An allergen test is essential because it may be hard to determine the root cause of your reaction if it appears hours after your allergen contact.

Types of private allergy testing offered at OneWelbeck

We offer a comprehensive selection of different allergy tests including food, skin, respiratory, drug and chemicals.

Allergy blood tests

Allergy blood tests measure the amount of IgE antibodies in your blood. When your body reacts to an allergen, it produces IgE antibodies. The presence of IgE antibodies may confirm an allergy. Your blood sample can also be tested against common allergens to determine what’s causing your allergy.  

In an allergy blood test, we’ll take a sample from a vein in your arm. Sometimes, more than one sample is taken depending on the number of tests needing to be performed. 

Our advanced technology and expert-led team can usually provide your results in 72 hours. Your dedicated allergist will review your results and provide all the advice and information you need to manage your allergy. 

Skin prick tests

Skin prick tests are one of the most prominent methods for diagnosing allergies. 

We can use skin prick tests to help diagnose allergies in:

Before you undergo a skin prick test, you will need to stop taking any antihistamine tablets for at least 48 hours. Otherwise, the results can be inaccurate. 

We usually perform skin prick tests on your inner forearm. Different drops of liquid containing different allergens are gently directed under your skin with a small lancet. Skin prick tests are slightly uncomfortable but not painful.

If you are allergic to any tested allergens, a small, itchy bump will appear after 10 to 15 minutes. We’ll record reactions and create a personalised allergy plan for you. 

ISAC tests

At OneWelbeck, we champion modern medical technology and use the latest advancements to provide accurate results. An ISAC test uses microchip engineering and technology to detect specific IgE antibodies.

We only need a small blood sample to perform an ISAC test to examine it against over 100 different allergens. We use microchip technology during the analysis to detect IgE antibodies and provide enhanced, detailed results.     

Patch testing for contact allergies

Our dermatologists can conduct patch tests to determine whether you have an allergy to chemicals that come into contact with the skin. This usually results in eczema or dermatitis. These are examples of delayed allergic reactions.

A patch test could be used to help diagnose the following allergies: 

  • Constituents of cosmetics including fragrances and preservatives

  • Medicaments eg constituents of treatment creams/drops/some oral medications

  • Hair dye allergy

  • Metals such as nickel 

  • Rubber chemicals

During a patch test, we place small amounts of different allergens into plastic chambers on adhesive tape, which is then stuck onto your upper back or upper arm. The tape will stay on your body for 48 hours. Once removed, we’ll record any reactions to the allergens and review the areas again two days later, to advise you about any allergens and how to avoid them.     

Drug provocation test

Certain medications like aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) can cause allergy symptoms in some people and worsen asthma.

To check if you have an allergy to a medication, we conduct a drug provocation test (or challenge). You’ll be given a dose of the suspected allergen (medication) and the dose will be slowly increased to determine if you have an allergy or not. 

Most of the time, this test is performed with you knowing what drug is being given. However, there are blinded challenges where you (single-blind) or both the patient and doctor (double-blind) do not know whether a real dose of the medication is being given or a placebo.

This test can take between two and six hours, depending on the drug being tested and the severity of your reaction. Sometimes, you must retake the same medication after a few days to rule out a potential delayed allergic reaction. 

Oral food challenge (OFC)

Food allergies are common and an oral food challenge is one way to rule them out or diagnose them. We’ll give you a small serving of the food you’re potentially allergic to and monitor your response for 15 to 30 minutes. If you have no symptoms, a slightly larger amount will be eaten. This will continue until you start to present allergic reaction symptoms or can eat a meal-sized portion of the food.

We’ll monitor you the entire time, minimising the risk of you experiencing a severe allergic reaction like anaphylaxis. If you have an allergic reaction, you may stay under observation for up to four hours to make sure your symptoms improve before you go home. 

OFCs are normally carried out if other allergy tests are inconclusive. Most of the time, OFCs are performed openly so you and the doctor will know what’s being eaten. However, they can sometimes be carried out single-blind or double-blind. 

Paediatrics allergy testing

At OneWelbeck, we also carry out allergy testing for children. Our paediatric food allergy prevention assesses your child’s risk of developing a food allergy and provides a diet plan to reduce their risk of common ones. They may also undergo skin prick testing.

We understand the worry of suspecting your child has an allergy. Our experts will ensure your child is always safe and monitor their reactions to the allergens. We will quickly treat signs of a more severe allergy to ensure your child is protected.

Are there any risks during allergy testing?

Allergy testing is low risk as we take every care and precaution to ensure you or your child are well looked after. However, there is a small risk of an adverse reaction during drug provocation tests and oral food challenges. If a reaction occurs, we will treat you immediately and bring your allergy under control.  

For fast, accurate results, book an allergy test with OneWelbeck. Our allergy team will guide and support you every step of the way so that you can take control of your allergies.  

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Jul 2024


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Self-Pay Available

This treatment is available for self-paying users. If you would like to see more information on pricing visit our pricing and payments page.


Consultation Required

For this treatment you will need to have a 1-to-1 consultation at OneWelbeck first. To book in with our team of expert clinicians or to find out more about the process contact the relevant centre team.


Self Referral

No doctor referral needed in order to book this service, although health insurers may require a referral in order for your treatment to be covered.

Allergy testing specialists

By having a complete and integrated team of sub-specialty experts under one roof we ensure that patients are seen by the right consultant at every appointment. Our allergy specialists are recognised leaders in their field and cover a wide range of dermatological conditions and allergies.