What is pruritus?
Itchy skin or pruritus is an irritating sensation on the skin that leads to an urge to scratch the affected area. It may be felt over the entire skin surface (generalized) or may be restricted to a small area on the skin (localized). Itching can occur due to many underlying causes and is a symptoms of various diseases, both of the skin and other systems and organs.
What are the symptoms of pruritus?
Itchy skin is actually a symptom, although sometimes pruritus may appear to occur on its own as a medical condition. Itch or irritation of the skin with or without a rash is the major feature. The rash may vary in presentation from bumps, redness, rough skin to blisters. In some cases the skin may become dry or cracked and some times it can even change into leathery or scaly texture. Although the itching is often relived by scratching, there are some conditions where scratching worsens the itching.
What causes pruritus?
One of the major cause of itchiness is dry skin (xerosis or xeroderma). This can be caused by environmental conditions, which include hot or cold weather with low levels of humidity, prolonged use of air conditioning or central heating and excessive washing or bathing. It can also be caused by several other disorders :
- Skin diseases or rash can be caused by several skin conditions which include eczema, chicken pox, psoriasis, lice and scabies. Some of these are infectious conditions. This is accompanied by redness or bumps or blisters on the skin and is restricted to small areas around the affected skin.
- Chronic illnesses such as liver disease or kidney failure, iron deficiency anemia, imbalance of thyroid hormones and rarely due to certain cancers such as leukemia. Disorders of the nervous system such as multiple sclerosis, diabetes mellitus, etc can lead to itchy skin. The skin looks normal and this usually affects the skin over the entire body.
- Allergic reaction and irritation due to external substances such as wool, chemicals, soaps. Food allergies or allergies to certain cosmetics can cause itchy skin
- Reaction to certain drugs such as antibiotics, antifungals or narcotic pain medication can cause itching on the skin of the entire body and is usually accompanied by rash
- During pregnancy some women develop an itchy skin especially around the abdomen, breasts, arms and thighs
- Prolonged itching can lead to bacterial infections on the skin. Further, it can also lead to neurodermatitis wherein the scratched area of the skin becomes leathery and thick.
How is itchy skin treated?
Itch due to dry skin is treated by topical application of moisturizing creams. An anti-itch cream such as those containing hydrocortisone may be used to relieve the itch. An oral antihistamine, such as diphenhydramine or topical application of corticosteroids may be prescribed when the itch is severe or due to an allergic reaction. These are the main approaches to treating itchy skin.
However, treatment should always be directed at the underlying cause and the itching tends to resolve. Avoiding the allergen or substances which irritate the skin, applying a cold wet compress on the skin, and avoiding scratching would help to reduce the itch while the underlying disease is being treated.
Emollients and calamine lotion are two common over-the-counter items that can help with controlling itch. In severe cases, even anesthetics like lidocaine may be used on the skin surface.