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"What is this rash near my joints?"

ZocdocAnswersWhat is this rash near my joints?


There is a red, somewhat itchy rash where my arms and knees bend. Like behind my knees and on my arms on the other side of my elbow. Is this a skin condition or just a rash caused by heat/sweat?


Based on the location of this rash, I am almost certain that you have atopic dermatitis. Atopic dermatitis is an allergic condition of the skin that is very common in people who have a personal or family history of asthma, food allergies, and other allergic conditions. Recently, we have been learning a great deal about what causes atopic dermatitis, and we now know that at least in part it is due to the absence of certain proteins in the skin layers that trap water. As a result, the skin has a tendency to dry out. When it dries out, it becomes itchy, inflamed, and it may crack or peel. Atopic dermatitis can affect any part of the skin, but it very classically affects the bends behind the knees and in front of the elbows. Fortunately, the condition can usually be brought under control with good skin moisturizing, using a thick "greasy" moisturizer, preferably with a vaseline consistency. This traps in moisture and prevents itching. If this does not work, it is often helpful to add a steroid ointment to help decrease inflammation. Your dermatologist or your primary care doctor can confirm the diagnosis and prescribe a steroid cream for you.

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