Causes

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

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
• 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 planus an itchy rash of unknown cause
• psoriasis askin 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 conditioncaused by inflamed hair follicles
• prurigo small blisters that are very itchy

Allergies and skin reactions

Itching is sometimes caused 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
• 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 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 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 causesa 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 afungal infection that causes a ring-like red rash to develop on theskin, and can also cause an itchy scalp
• vaginal thrush or thrush in men yeast infections that can cause itching in and around the genitals

Otherconditions

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
• an overactive thyroid or underactive thyroid where the thyroid gland in the neck produces toomuch 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 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, 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 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.

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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.