I am no doctor but I have had very itchy skin many times.
Usually it is caused - or at least made worse - by dryness.
I use organic coconut oil - the kind you can eat like butter - on my skin, and since then I have had little or no problems.
Xerosis is the medical term for dry skin.When it results in skin that is scaly and itchy, the condition is called pruritus. This occurs when natural moisture is drawn out of the skin.
The skin needs moisture to protect itself. The best way to relieve dry skin is to use a moisturizer. Too much water can cause the skin to dry out. Habitually showering or bathing more than once a day should be avoided to prevent dry skin.
It can have many different causes, including general dehydration, Vitamin A deficiency, and diabetes.
Externa factors affecting skin are washing with excessively hot water, using nonmoisturizing soap, showering or bathing more than once a day, and bathing for long periods of time.
Environmental factors such as excessive sun exposure and pollutants in the air can damage the skin. Dry skin is often a problem in cooler climates, especially during winter months when home heating systems are used regularly. This unhumidified heat is dry and draws moisture from the skin. Outdoors, cold winter air causes the body to protect itself by drawing blood away from the skin. When this occurs, the skin is not well nourished and xerosis can result.
Emollients are creams that can be applied to the affected area to prevent water from evaporating from the skin's surface. Emollients also smooth over the scaly edges that can flake off and cause intense itching. Emollients should be applied after bathing and frequently throughout the day.
Oils can be added to bath water, but they are not as effective as emollient creams.