Itching - Causes of itching

An itch is often caused by a condition affecting the skin, but it can be a sign of a more serious underlying problem.

In some cases, it may not be possible to identify a specific cause.

Skin conditions

Skin conditions that can cause itching include:

dry skin
eczema – where the skin is dry, red, flaky and itchy
contact dermatitis – inflammation of the skin that occurs when you come into contact with an irritant or allergen (see below)
urticaria – also known as hives, welts or nettle rash; urticaria is triggered by an allergen and causes a raised, red itchy rash to develop
lichen planus – an itchy rash of unknown cause
psoriasis – a skin condition that causes red, flaky, crusty patches of skin covered with silvery scales
dandruff – a common skin condition that causes dry white or grey flakes of dead skin to appear in the scalp or hair
folliculitis – a skin condition caused by inflamed hair follicles
prurigo – small blisters (fluid-filled swellings) that are very itchy

Allergies and skin reactions

Itching is sometimes caused by an allergen, irritant or other environmental factor, including:

cosmetic ingredients, such 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 resins that are contained in them
some plants – such as chrysanthemums, sunflowers, daffodils, tulips and primula
an allergy to certain foods or types of medication (for example, aspirin and a group of medicines called opioids)
prickly heat – an itchy rash that appears in hot, humid weather conditions
sunburn – skin damage caused by exposure to ultraviolet (UV) rays

Parasites and insects

Itching can be caused by the following pests:

the scabies mite, which burrows into the skin and causes a skin condition called scabies
head lice, pubic lice or body lice
insect bites and stings from bees, wasps, mosquitoes, fleas and bedbugs
threadworms – small worm parasites that infect the bowels of humans and can cause an itchy bottom
trichomonas vaginalis – a tiny parasite that causes a sexually transmitted infection (STI) called trichomoniasis

Infections

Itching may be a symptom of an infection, such as:

chickenpox or another viral infection
athlete's foot – a fungal infection that causes itching in between the toes
ringworm – a fungal infection that causes a ring-like red rash to develop on the skin and can cause an itchy scalp
vaginal thrush or thrush in men – yeast infections that can cause itching in and around the genitals

Other conditions

Itching can be a sign of an underlying condition that may affect the inside of the body without necessarily causing any other obvious symptoms.

Itching can be a symptom of:

haemorrhoids (piles) – enlarged and swollen blood vessels in or around the lower rectum or anus
an overactive thyroid or underactive thyroid – where the thyroid gland in the neck produces too much or too little thyroid hormone
iron deficiency anaemia – where a lack of iron in the body leads to a reduction in the number of red blood cells
polycythaemia – where you 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, including liver cancer, pancreatic cancer, leukaemia and Hodgkin lymphoma

Occasionally, itching can be linked to a psychological condition such as depression or anxiety.

Pregnancy and the menopause

In women, itching can sometimes be caused by hormonal changes during pregnancy and after the menopause.

Pregnancy

Itching often affects pregnant women and usually disappears after the birth. A number of skin conditions can develop during pregnancy and cause itchy skin. They include:

pruritic urticarial papules and plaques of pregnancy (PUPPP) – a common skin condition that causes itchy, red, raised bumps that appear on the thighs and abdomen (tummy)
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.

Menopause

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.