What is pruritis?
Pruritis is the medical word for itch. It is defined as a sensation that provokes the desire to scratch. Itching can be a significant source of frustration and discomfort. When severe, it can lead to loss of sleep, anxiety, and depression.
What is the cause?
The exact cause of an itch is unknown and is a complex process. It involves nerves in the skin responding to certain chemicals such as histamine, and then processing these signals in the brain. Pruritis can be a symptom of certain skin diseases, and sometimes a manifestation of an internal process. In other patients where there is no evidence of skin or internal disease, pruritis may be due to faulty processing of the itch sensation within the nervous system.
There are many skin diseases that have itching associated with a rash as a prominent symptom. Examples would be hives, chicken pox and eczema. Some skin conditions only have symptoms of pruritis without having an apparent rash. Dry skin, for example, is very common in the elderly, and can really itch (especially in the winter), with no visual signs of a rash. Pruritis is usually secondary to subtle dry skin, but it may be a manifestation of an internal condition. Some parasitic infestations of the skin, such as scabies and lice, may be very itchy.
There are several internal diseases that may cause itch. The most common example is kidney failure. Other types of internal diseases that may cause pruritis are some types of liver disease including hepatitis C, and thyroid disease. Some blood disorders such as iron deficiency anaemia and multiple myeloma can cause itch. Occasionally, lymphomas may have pruritis as a component. Neurologic conditions such as pinched nerves and strokes may also lead to an itch.
What is the treatment?
The doctor will first try to determine the cause of the itch. This requires an examination of the skin and possibly a blood test or a biopsy. If the itch is from a skin disease such as hives or eczema, treatment of the skin disease itself generally relieves the itch. If the itch is from an internal disease, patients may require medication to be taken orally, or occasionally may receive ultraviolet light treatments to relieve the itch.
Although there are many causes for pruritis, there are some basics that apply to most treatments. First of all, hot bathing or showering should be avoided. Only bathe in lukewarm water. Wearing light clothing, and a cool work or domestic environment all help to reduce the severity of itching. Soaps often dry out the skin. Use mild soaps only in odour bearing regions. After bathing, be sure to completely rinse off the soap film, pat the skin lightly, and immediately apply a moisturising lotion or cream. Although pruritis is an often disrupting and disabling symptom it generally responds well to treatment.