Symptoms include a rash, itching, swelling, raised bumps, redness, cracked, scaling or flaking skin.
A skin allergy occurs when your body's immune system has an unusual reaction to a specific allergen. This is normally something harmless, but the immune system mistakes the allergen as a threat and releases antibodies, which attack the area to protect it, resulting in a skin reaction.
There are several types of allergic skin conditions. Contact dermatitis, is skin inflammation caused by contact with something in the environment. There are two types, one caused by irritants that strip the skin of its natural oils such as detergents and chemical solvents and another caused by contact with a substance you have become allergic to including nickel, rubber, perfumes and hair dyes.
Atopic eczema is a chronic skin condition where sufferers have an increased sensitivity to foods, inhaled substances or those that are in contact with the skin.
Other skin conditions that cause skin allergy include: a rash triggered by exposure to sunlight or UV light, known as polymorphic light eruption; hives, also known as urticaria and caused by infection; medications; hot or cold exposure; a food allergy; or an insect bite. A quarter of people with hives will go on to develop angioedema, a deeper swelling underneath the skin, also affecting other parts of the body including the eyes and lips.
With a skin allergy, you may experience one of the following, or a combination – itching, swelling, a rash, redness, raised bumps, scaling and cracked skin.
In cases of atopic and dermatitis eczema, the crusted skin may leak fluid, which can be an indication that it's infected.
Your GP may be able to diagnose a skin allergy from symptoms and by asking about the triggers. It may be useful to keep a trigger symptom diary to track flare-ups.
Skin prick tests, where the skin is pricked with a tiny amount of the allergen to see if there's a reaction, may be carried out to find out what you are allergic to. Other tests include a specific IgE blood test, which measures the amount of IgE antibodies that are produced by the immune system in response to an allergen; and a patch test, where a small amount of the suspected substance or chemical is taped on the skin for 48 hours to see if the skin reacts.
Who gets skin allergies?
Skin allergy can occur at any age. Studies suggest allergy may be related to genes and environmental factors. Some professions have a higher risk of developing dermatitis, such as cleaners, beauticians, hairdressers, construction workers and nurses (if they work with irritants).
Treatment options will vary according to the cause. Firstly, it's important to avoid the allergen and irritant that causes allergic reactions.
Skin allergy drugs, creams and ointments can help manage the symptoms and reactions. These include antihistamine tablets and syrups, which block the action of histamine, a chemical released by the immune system during an allergic reaction.
Emollient lotions and creams can relieve symptoms by moisturising and creating a barrier on the top layer of the skin to protect it. Topical steroid creams reduce inflammation and redness during flare-ups. Calcineurin inhibitor creams can reduce inflammation and itching by lowering the sensitivity of the immune system when an allergen comes into contact with the skin. Calamine lotion can ease itchy skin.
It's important to avoid scratching the skin as this can cause more damage and worsen the condition, as well as setting off the scratch/itch cycle. Where a food allergy is suspected, you may have to change your diet, but this should be under specialist supervision.
Immunotherapy, also known as desensitisation, may be used as a treatment option for severe and persistent allergies. This is where tiny doses of the allergen are given over a period of years, via injection, a tablet or drops, with the intention that the immune system learns to tolerate it.
Collagen supplements may help skin damaged by eczema to heal. One study found oral collagen tripeptide treatment was an effective therapy for wound healing and skin recovery. Evening primrose oil (EPO) may also ease the symptoms of dermatitis. A study of 21 children and adults with atopic dermatitis, who each took 4,000 to 6,000mg of EPO a day for 12 weeks, concluded EPO supplements may significantly improve symptoms in patients with clinical atopic dermatitis.