Itching can cause constant tingling or skin sensations that promote scratching. It occurs from irritations to the nerve cells along the skin. Itching may develop from several sources, including allergic reactions, skin problems and medications. Constant itching can affect certain parts of the skin or cause widespread skin eruptions.Those who experience constant itching tend to have other symptoms associated with it. A health care provider can assist in diagnosing and treating constant itching.
Psoriasis
Psoriasis is a long-term skin condition that causes a rapid buildup of skin cells. The skin condition develops from overreactions of the immune system. Normally, skin cell production takes about four weeks between shedding and growth of new skin cells. The abnormal immune reaction instead causes skin cell production in just days. The National Psoriasis Foundation reports that as many as 7.5 million Americans and 125 million people worldwide have psoriasis. Symptoms of psoriasis include persistent itching, red patches, thickened skin and dry, scaly areas that may bleed. Stress, dry skin, certain medications and infections can make psoriasis worse.
Allergic Contact Dermatitis
Allergic contact dermatitis occurs from allergens or irritants that come in contact with the skin. The skin condition causes mild to severe skin reactions that can appear anywhere on the body. Symptoms of allergic contact dermatitis include itching of the exposed areas, tenderness, redness, localized swelling, skin lesions and rashes. The rash usually doesn't show for up to two days, but can start as soon as an hour or as late as a week, notes the American Osteopathic College of Dermatology. Following the rash the skin may darken and crack if not treated. Common allergens that cause allergic contact dermatitis include rubber, dyes, nickel, poison ivy, fragrances and many skin care products.
Scabies
Scabies is an itchy and highly contagious skin disorder caused by the Sarcoptes scabei mite. The microscopic mite burrows into the surface of the skin where it lives and lays eggs. Common sites for infestation include between the fingers and toes, around the waist, on the knees and shoulders, buttocks, soles of the feet, neck and palms of the hand. The most prominent symptoms of scabies are intense itching particularly at night, rash, irritations and sores caused by scratching. Symptoms can take up to two months to appear for those infested with scabies for the first time, and an infected person can still transmit scabies, warns the Centers for Disease Control and Prevention. Scabies mites can be transmitted from direct skin-to-skin contact, sexual contact and indirect transfer from clothing.
