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Allergic contact dermatitis
Mate harehare pānga pāwera
Allergic contact dermatitis is when your skin comes into contact with something you're allergic to (called an allergen).
It's different to irritant contact dermatitis because while irritant contact dermatitis can affect anyone, you'll only get allergic contact dermatitis if you're allergic to certain things that touch your skin.
Allergic contact dermatitis happens due to an allergic reaction to a chemical or substance that causes your body to have an immune reaction. Many things can cause this, the most common are nickel (in a lot of jewellery), rubber (latex), hair dyes, some plants (such as ivy), and chemicals in make-up, soap, skincare products, and plasters.
Symptoms of allergic contact dermatitis
If you have allergic contact dermatitis, you'll develop an itchy rash after coming into contact with the allergen. For example, you may get a rash on your eyelids if you're allergic to a chemical in your make-up or a rash under your watch strap if you're allergic to nickel.
The rash usually occurs a few hours after the contact, not within a few minutes like with hives. Your skin can become red, sore and swollen. This will settle down after a few days as long as your skin is no longer in contact with the allergen.
Diagnosing allergic contact dermatitis
Your GP can usually diagnose allergic contact dermatitis by the appearance of your skin. They will ask you questions about your symptoms, including when they first appeared, what you're in contact with and what worsened the symptoms. With your help, your GP will try to identify the allergen.
Laboratory tests are not usually required but if it's not obvious what the allergen is, you might be referred to see a dermatologist (skin doctor) for patch testing. You can read about patch testing on DermNet NZ.
If you think your make-up or skincare products are causing allergic contact dermatitis, you can test them at home with a simple test (called the open user test). Put the product onto a small area of sensitive skin (such as the inside of your upper arm) twice a day for five to 10 days in a row. If you get a rash there, it's likely you have allergic contact dermatitis. This is a useful way to check your products so you can stop using anything that causes problems.
Treating allergic contact dermatitis
Treatment includes:
- Avoiding contact with whatever you are allergic to – this is the main treatment for allergic contact dermatitis.
- Using emollients (topical moisturisers) on any affected area. These moisturise your skin to help rehydrate it and provide a barrier that helps your skin heal.
- Applying topical steroids. These are anti-inflammatory creams that you put directly onto your skin. A mild steroid cream with 1% hydrocortisone, which you can buy from a pharmacy, may help it to settle down more quickly. Ask your pharmacist for advice as to what cream is best for you.
Getting help for allergic contact dermatitis
See your GP if the rash is severe, affecting a large area, or if it doesn't improve with hydrocortisone cream after a few days. You might need stronger steroid creams or even steroid tablets (prednisone) to heal the redness and itch.
Your GP may refer you to a dermatologist (a specialist skin doctor). If you prefer, you can pay to see a private dermatologist. You can find a dermatologist on Healthpoint.
HealthInfo recommends the following pages
- DermNet NZ – Allergic contact dermatitis
Information about allergic contact dermatitis including what causes it and how it's treated.
Written by HealthInfo clinical advisers. Last reviewed August 2021.
SourcesReview key: HICOD-326084
