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Patch testing for contact dermatitis

Patch testing

Patch testing for contact dermatitis

Allergic contact dermatitis can be provoked by many chemicals, which can make discerning the origin of the reaction challenging. After all, different people react in different ways to different things. Often what triggers an allergic response in one individual will see no reaction in another. Despite this, it often manifests under the umbrella term of ‘eczema’ on any individual, regardless of that original cause. Thankfully, there are ways to narrow down the search. If you want to determine which specific substance is causing the inflammation, you might want to consider patch testing.

Patch testing helps to distinguish which substances may be causing an allergic reaction in a patient’s skin. It’s a useful puzzle to solve as the contact allergy can damage the skin. You can use other tests (such as blood testing) to look for sensitisation to fungal allergens. The problem with this though is that it might be only the aggravating factor, not the causative on. A patch test is a provocation test; the intention is to produce a local allergic reaction on a small area of the patient’s back, where the diluted chemicals are placed on a plaster.

Testing, 1, 2, 3

The initial process of patch testing generally takes no longer than around half an hour to apply the patch, though this can vary based on the number of allergens you are testing for. After 48 hours the consultant will remove the patches. However, it’s important to remember that the results of patch testing will not occur immediately after the removal of the plaster. Not everyone will see positive results; it can take between 2-4 days for a reaction to occur. After this period, you will return for a third appointment, and the consultant will record which of the allergens have yielded a noticeable effect on the skin.

It’s also important to note that patch testing only tests for contact dermatitis triggered by chemicals, and not other types of allergy. In the case of food allergy or respiratory symptoms, you may also require a blood test or skin prick test. These processes can indicate allergic reactions to stimuli that do not provoke the same response as contact dermatitis.

The intention of patch testing is to indicate what is causing the allergic response, and when identified the patients will need to avoid the allergen that triggers the reaction. Ultimately, once you know what is causing your contact dermatitis, you can begin to adjust your lifestyle in ways that avoid as much contact with the implicated allergen as possible. For optimal skin health, maintaining a great skincare regime is vital and is likely to prevent further skin infection.

You can only carry out patch testing on the recommendation of a consultant. Our consultant will review your condition and advise if contact allergy is suspected and when patch testing can be done. Please book an appointment with one of our staff.

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