Itchy human skin can be caused by both internal and external conditions. According information on itching by the Mayo Clinic, some of the most common causes of itchy human skin include skin conditions, rashes, internal diseases and allergic reactions. If you experience painful, discolored or severe itchy skin, contact your physician.
Dermatitis or Allergic Reactions
One type of dermatitis that causes itchy skin is called contact dermatitis. Contact dermatitis usually occurs when your skin comes into contact with certain substances that irritate the skin. According to the University of Maryland Medical Center, irritant dermatitis, which is the most common variety of contact dermatitis, encompasses inflammation of the skin that results from contact with alkaline materials or acids contained in soaps, laundry detergents, solvents and other kinds of chemicals. The reaction usually bears a resemblance to a burn but also causes itchy human skin. Another type of dermatitis is atopic dermatitis–also known as eczema–which can also cause itchy human skin. Other symptoms include small red bumps, scaly or flaky skin and red or brown patches of skin. The cause of atopic dermatitis is not known, but the Mayo Clinic reports that it may be due to a combination of dry skin and a fault in the body’s immune system.
Psoriasis
Psoriasis is a condition that affects the skin and causes itching. Psoriasis occurs when cells under your skins surface build up too fast on the surface of the skin. According to Medline Plus, psoriasis can cause itchy or sore patches of dense, red skin. The red skin may also appear silver or scaly. You typically get red patches on your back, elbows, knees, scalp, neck, face, inside the hands and feet, but they can appear on other parts of the body as well. Treatment for psoriasis is focused on interrupting and slowing the cell production cycle. Topical treatments, oral medication and light therapy are ways to help with psoriasis.
Other Diseases
In some instances, itchy human skin can be caused by the presence of an internal condition or disease. According to information on itchy skin by the Mayo Clinic, diseases likely to cause itching include disease of the liver, failure of the kidneys, iron deficiency, problems with thyroid and certain kinds of cancers–including lymphoma and leukemia. In cases where the presence of disease is the cause of itching, the itching will usually affect the entire body, rather than one particular area. In certain instances the skin may appear normal aside from the areas being scratched.
