This leaflet gives a brief overview of itching when no cause can be found for the itch. Various other leaflets discuss conditions where the cause of the itch is known, such as eczema or urticaria.
What is itch?
Itching (pruritus) is a symptom that can be caused by a large number of conditions. Sometimes itching is caused by a skin condition, such as eczema or hives. You would usually have a rash to see if this is the case. Other times, itching is caused by a more general illness, such as jaundice or chronic kidney disease. Itching is also common in pregnancy. Sometimes you itch in a specific place. Itch of the back passage (anus) and itch of the external sex organs of a woman (her vulva) are common, for example, and have various causes. These conditions are also known as pruritus ani and pruritus vulvae. See separate leaflets called (Itchy Bottom (Pruritus Ani) and Itchy Vulva (Pruritus Vulvae) for more details.
However, in many cases no cause is found for an itch. This article deals only with itch that is not due to any underlying skin or medical condition. This is called itch of unknown cause.
If you are not sure why you are itching, you should see your doctor. If no cause for an itch is obvious, then your doctor may suggest some blood tests to see if there is an underlying cause for the itch. However, in many cases, the tests are normal and the cause remains a mystery.
Itching can occur over your entire body or just in one area. It can be very unpleasant and uncomfortable.
One possible factor is that in some people with itch of unknown cause, their skin may be drier than average, which may contribute to the itch. Itch of unknown cause is most common in older people whose skin tends to be drier than that of younger people. Itch tends to be worse at night and may be made worse by bathing. Any part of the skin may be affected.
What are the treatments for itching of unknown cause?
The following may help to improve your itching:
- Keep your nails short to limit any damage done to your skin by scratching. As much as possible try not to scratch. It is thought that scratching can make itch worse and you may get into an 'itch-scratch' vicious cycle. (That is, you itch more because you scratch, so you scratch more because you itch more ... and so on.)
- Keep cool as much as possible. Some people find having cool (or lukewarm) baths or showers soothing.
- Avoid irritants such as soaps, bubble bath and detergents. Cotton clothes are usually preferable to woollen clothes.
- Moisturisers (emollients). Dry skin may be making the itch worse. Moisturisers are useful to keep the skin supple and moist. They can be applied once a day or several times a day if your skin becomes very dry. Water and soap dry out the skin as they wash away the natural skin oils. Therefore, the most important time to use moisturisers is after a bath or shower. Moisturisers work by providing a replacement for these body oils and keeping the skin moist. Numerous moisturisers are available as creams, ointments and bath/shower additives, and also to use instead of soap. It may be worth trying out a few to see which is the most suitable. These can be bought over-the-counter or different ones are available on prescription from your doctor. Use them liberally, as often as needed.
- Antihistamine medication is sometimes tried. Antihistamines are useful for some skin conditions that cause itch such as urticaria. However, they do not help with all types of itch. For itch of unknown cause they may have little effect. Some antihistamines also tend to make you drowsy. However, these types of antihistamines may be worth trying at bedtime if itch is troublesome at night. An example is chlorphenamine. Your doctor or pharmacist can advise you further.
- Relaxation techniques can be beneficial for some people. A brain-training treatment called cognitive behavioural therapy (CBT) may also be helpful. This helps you to break the itch-scratch cycle.
- Certain antidepressants. These may occasionally be prescribed when itching is very distressing. They work by helping to tone down the chemicals in the brain which make you feel an itch and want to scratch.
The amount of discomfort from itch can vary from person to person, and in its frequency in the same person . A referral to a skin specialist may be advised if your itching persists or is severe. There are different treatments which are being investigated in clinical trials which may be available in the future.
Further reading and references
; A diagnostic approach to pruritus. Am Fam Physician. 2011 Jul 1584(2):195-202.
; NICE CKS, November 2015 (UK access only)
; Advances in understanding itching and scratching: a new era of targeted treatments. F1000Res. 2016 Aug 225. pii: F1000 Faculty Rev-2042. doi: 10.12688/f1000research.8659.1. eCollection 2016.