Itching

What is itching?

Itching (medically referred to as pruritus) is an uncomfortable sensation of the skin that leads to the desire to scratch. Itching is extremely common. Some people itch a little while others itch a lot. Sometimes it reaches the point where it significantly reduces quality of life and ability to sleep.

What causes itch?

The sensation of itching arises from irritation of the nerve cells associated with the skin. The nerves that are the source of itching are known as C-fibers. Activation of these nerves gives us the desire to scratch to try to relieve this sensation. The nerves in the skin can become irritated for a variety of reasons. Some of the major causes include dryness, skin inflammation, temperature changes, and release of chemical mediators within the skin due to underlying skin disease.

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There are several skin diseases that lead to itching. These include common inflammatory skin diseases such as psoriasis and eczema. Itching may also be associated with skin infections.  Simply living in a low-humidity climate such as Idaho which leads to dry skin can cause a significant amount of itching. Various types of skin growths, and even skin cancers can lead to itching. Systemic diseases such as thyroid, liver, or kidney disease can also lead to significant and severe itching. Sometimes the itching is due to actual disease of the nerves due to conditions such as diabetes or trauma to the nerves. Rarely itching can even be a sign of internal malignancy.

What evaluations or testing do I need for itching?

The first step is to see a qualified skin specialist such as a dermatologist. Often there is a simple and easily identifiable cause of itching and the proper prescription or treatment plan can be prescribed. If the cause of itching is unclear, labs including blood work or a skin biopsy where a sample of skin is removed and looked at under the microscope may be performed. If none of the common causes of itching are found or if a patient doesn't respond to treatments, further evaluations such as x-rays or CT scans may be done to look for cancer or other causes. These types of tests looking for cancer are rarely needed as a more common cause is usually found. 

How is itching treated?

Treatment is best guided by receiving a correct diagnosis. If a diagnosis is found therapy can be directed at that cause. These may include use of topical or systemic steroids to reduce inflammation, antifungals or antibiotics to kill infections, or use of anti-itch creams. If the cause of itching is thought to be from a nerve disease, medications that work to calm the nerves in the skin may be used. Unfortunately there is no treatment that is universally effective for itching and multiple types of treatment may be needed.