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Testing needed to identify two different forms of eczema


A new article published in the Journal of the American Academy of Dermatology reveals that children diagnosed with atopic dermatitis – which they usually develop by 5 years of age – may also need to be tested for a second type of eczema called allergic contact dermatitis.

The latter has similar symptoms and can be triggered by a range of substances that cause an allergic reaction.

Broadly speaking, eczema, is a group of medical conditions that causes inflamed, irritated and often itchy skin, which affects millions of people worldwide.

“When a dermatologist sees a child who looks like they have eczema, we usually think that it's atopic dermatitis because nearly one in five children develop it,” said board-certified dermatologist JiaDe (Jeff) Yu, MD, MS, FAAD, assistant professor of adult and pediatric dermatology at Massachusetts General Hospital and senior author of the published research study. “Sometimes these kids could have allergic contact dermatitis, but the only way to tell is through patch testing, which is designed to identify substances that may be irritating your skin.”

Poison ivy, poison oak and poison sumac are the most common causes of allergic reactions in the United States. Other common causes of allergic contact dermatitis include metals (such as nickel), rubber, dyes, cosmetics, preservatives and fragrances.

Treatment options for atopic dermatitis include steroids that can be applied to the skin, phototherapy, which uses ultraviolet light to reduce inflammation and ease itch, medications called ‘biologics’ that work throughout the body, and medications that are used to suppress the immune system, such as JAK inhibitors, Dr Yu said. While these options also can be used to treat allergic contact dermatitis, identifying and avoiding substances that are causing the allergic reactions is most effective in helping improve a patient's condition and to clear their skin.

Lifestyle changes can also relieve eczema symptoms, he said, and it's important to choose fragrance-free products because fragrances can contribute to flare-ups. People with eczema should test new skincare products first by applying them to a quarter-sized patch of skin on the inside of the arm every day for four weeks. If there is no reaction, the patient will likely be able to use the product.

Dr Yu emphasized the need for people who show signs of having eczema to consult a dermatologist, who can determine whether a patient has atopic dermatitis, allergic contact dermatitis, or both.

“Patients can have atopic dermatitis and allergic contact dermatitis at the same time, and it all looks like the same thing,” he said. “I imagine it like layers of a cake. Maybe the first layer is atopic dermatitis, and then the second layer is allergic contact dermatitis. In these cases, the overall eczema may look very severe but once you remove the allergic component, the eczema seems much more manageable. A dermatologist can provide you with an accurate diagnosis by performing a patch test to determine whether you have allergic contact dermatitis and determine how to appropriately treat it.” Source: American Academy of Dermatology;

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