Contact dermatitis is a red, itchy rash caused by direct contact with a substance or an allergic reaction to it. The rash isn't contagious or life-threatening, but it can be very uncomfortable. Many substances can cause such reactions, including soaps, cosmetics, fragrances, jewelry and plants. And Nickel. Nickel is the most frequent cause of allergic contact dermatitis. To help reduce itching and soothe inflamed skin, try these self-care approaches: Avoid the irritant or allergen. ... Apply an anti-itch cream or lotion to the affected area. ... Take an oral anti-itch drug. ... Apply cool, wet compresses. ... Avoid scratching. ... Soak in a comfortably cool bath. ... Protect your hands.