An itch is often caused by a condition affecting the skin, but it can occasionally be a sign of a more serious underlying problem.
In some cases, it may not be possible to identify a specific cause.
Skin conditions that can cause itching include:
- dry skin
- eczemawhere the skin is dry, red, flaky and itchy
- contact dermatitisinflammation of the skin that occurs when you come into contact with an irritant or allergen
- urticaria also known as hives, welts or nettle rash; it is triggered by an allergen and causes a raised, red, itchy rash to develop
- lichen planusan itchy rash of unknown cause
- psoriasisaskin condition that causes red, flaky, crusty patches of skin covered with silvery scales
- dandruffa common skin condition that causes dry white or grey flakes of dead skin to appear in the scalp or hair
- folliculitis a skin conditioncaused by inflamed hair follicles
- prurigo small blisters that are very itchy
Allergies and skin reactions
Itching is sometimescaused by an allergen, irritant or another environmental factor, including:
- cosmetic ingredientssuch as preservatives, fragrances, hair dye and nail varnish hardeners
- certain metals such as nickel or cobalt in jewellery
- rubber including latex
- textiles particularly the dyes and resinsthey contain
- some plants such as chrysanthemums, sunflowers, daffodils, tulips and primula
- anallergy to certain foods or types of medication for example, aspirin and a group of medicines called opioids
- prickly heatan itchy rash that appears in hot, humid weather conditions
- sunburnskin damagecaused by exposure to ultraviolet (UV) rays
Parasites and insects
Itching can be caused by the following pests:
- the scabies mite the mite burrows into the skin and causes a skin condition called scabies
- head lice,pubic lice or body lice
- insect bites and stingsfrom bees, wasps, mosquitoes, fleas andbedbugs
- threadworms small worm parasites that infect the bowels of humans and can cause anitchy bottom
- trichomonas vaginalis a tiny parasitethat causesasexually transmitted infection (STI) calledtrichomoniasis
Itching may be a symptom of an infection, such as:
- chickenpoxor another viral infection
- athlete's foot a fungal infection that causes itching in between the toes
- ringworm afungal infection that causes a ring-like red rash to develop on theskin, and can alsocause an itchy scalp
- vaginal thrushor thrush in men yeast infections thatcan cause itching in and around the genitals
Itching can sometimes be a sign of an underlying condition, such as:
- piles (haemorrhoids) enlarged and swollen blood vessels in or around the lower rectum or anus
- anoveractive thyroid orunderactive thyroid where the thyroid gland in the neck produces toomuch or too little thyroid hormone
- iron deficiency anaemiawhere a lack of iron in the body leads to a reduction in the number of red blood cells
- polycythaemia whereyou have a high concentration of red blood cells in your blood
- liver-related conditions, such as primary biliary cirrhosis and hepatitis
- long-standing kidney failure
- in rare cases, certain types of cancer, includingliver cancer, pancreatic cancer, leukaemiaand Hodgkin lymphoma
Occasionally, itching can be linked to a psychological conditionsuch asdepression or anxiety.
Pregnancy and the menopause
In women, itching can sometimes be caused by hormonal changes during pregnancy and after the menopause.
Itching often affects pregnant women and usually disappears after the birth. A number of skin conditions can develop during pregnancy and cause itchy skin.
- pruritic urticarial papules and plaques of pregnancy (PUPPP) a common skin condition that causes itchy red, raised bumps that appear on the thighs and tummy (abdomen)
- prurigo gestationis a skin rash that appears as red, itchy dots and mainly affects the arms, legs and torso
- obstetric cholestasis a rare disorder that affects the liver during pregnancy and causes itching without a rash
Seek advice from your midwife or GP if you have itching or any unusual skin rashes during your pregnancy.
Itching is also a common symptom after the menopause, which is where a woman's periods stop as a result of natural hormonal changes as she gets older.
Changes in the levels of hormones, such as oestrogen, that occur during the menopause are thought to be responsible for the itching.