Why Scratching an Itch Only Makes It Worse:
Scratching an itch gives only temporary respite before making it worse – we now know why.
Millions of people experience chronic itching at some point, as a result of conditions ranging from eczema to kidney failure to cancer. The condition can have a serious impact on quality of life. Due to this, the body appears to have a coping mechanism: scratching an itch until it hurts can bring instant relief. But when the pain wears off the itch is often more unbearable than before – which means we scratch even harder, sometimes to the point of causing painful skin damage.
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.
Scientists have discovered that Scratching triggers the release of a nerve chemical that intensifies the maddening sensation. The finding, in mice, suggests resisting the urge to scratch an itch has a scientific basis. Scratching is known to provide temporary irritation relief by generating a small amount of pain. For a short time, nerve cells in the spinal cord carry pain signals to the brain instead of itch signals. But that is when the trouble starts, researchers have discovered. The brain responds to the pain by releasing the nerve-signaling chemical serotonin, which stimulates more itching. This result is an itch/scratch/pain/itch vicious cycle. But then the brain releases a neurotransmitter called serotonin to dampen the pain, and in a new study, researchers found that this serotonin release also activates certain neurons in the spinal cord, which creates more itching sensations.
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 younger people. Itch tends to be worse at night and may be made worse by bathing. Any part of the skin may be affected.
Treatments for itching of unknown cause:
- Keep your nails short to limit any damage done to your skin by scratching
- 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.
- Dry skin may be making the itch worse. Moisturisers (emollients) are useful to keep the skin supple and moist.
- Antihistamine medication is sometimes tried. Antihistamines are useful for some skin conditions that cause itch such as urticaria.
- Relaxation techniques can be beneficial for some people.
- Occasionally certain antidepressants may be prescribed when itching is very distressing.
The amount of discomfort from itch can vary from person to person, and from time to time in the same person. A referral to a skin specialist may be advised if your itching persists or is severe. There are various treatments which are being investigated in clinical trials that may be available in the future.