What’s behind that maddening itch? Expert guide to causes and when to see a doctor

Chronic itching, or pruritus, is more common than many people realise, affecting at least one in six adults in the UK. While it may seem trivial, experts warn that an ongoing itch should not be dismissed, because scratching can perpetuate a cycle that disrupts sleep and daily life. In many cases, the underlying cause is treatable with over-the-counter moisturisers or prescription medicines, but identifying the trigger is key to relief.

Last week, GP columnist Dr Philippa Kaye invited readers to share their experiences of persistent itching. The response was overwhelming, with accounts of years of torment, misdiagnoses and ineffective treatments. A 79-year-old man described an unbearable itch on his back that lasted 12 years, while an 88-year-old reader spoke of four years of sleepless nights and depression. The stories underscored the impact itching can have on quality of life, and experts emphasise there is help available once the cause is identified.

Eczema affects around 1.5 million people in the UK. Also known as atopic dermatitis, it causes red, cracked patches that can be painful and disfiguring. It can even affect the ear canal. Scratching worsens the problem by damaging the skin and fueling an itch–scratch cycle. Emollients, which are over-the-counter moisturising treatments, and steroid creams can help reduce swelling, redness and itching. If eczema strikes inside the ear canal, avoid cotton buds, which can worsen dryness; instead, consider a few drops of olive oil or ask a GP about steroid drops.

In addition to eczema, fungal infections thrive in moist environments and are a common cause of itch. The skin hosts numerous fungi that can overgrow when moisture and warmth are present or when the immune system is weakened. Common sites include between the toes, the groin and under the arms. Ringworm presents as a red, circular rash with a raised edge, while jock itch and athlete’s foot are also frequent culprits. Mild infections often respond to OTC antifungal creams, but if symptoms persist beyond two weeks, involve the scalp, face or genitals, or recur, a GP may prescribe stronger tablets or medicated shampoo.

Tiny parasites can also cause a fierce itch. Scabies, caused by microscopic mites burrowing under the skin, spreads easily through close contact and is known for intense nocturnal itching and a distinctive rash in folds of the elbows, knees, buttocks and between fingers and toes. In uncertain cases a doctor may examine skin scrapings for mites or eggs. Treatment typically includes an anti-parasitic lotion applied to the whole body and left on for up to 12 hours, sometimes followed by a prescription pill such as ivermectin. Clothes, bedding and towels should be laundered on hot settings to kill remaining mites. The itching can persist for weeks after treatment but usually resolves with correct management.

Shingles, or reactivation of the varicella-zoster virus, can also produce a painful, itchy rash that tends to affect only one side of the body. Early antiviral treatment, ideally started within 72 hours of symptom onset, reduces the risk of prolonged pain and complications. In rare cases, the virus can affect the eyes, requiring urgent referral to an ophthalmologist.

Thyroid problems can manifest as skin changes, including itch. An underactive thyroid (hypothyroidism) slows skin cell turnover and reduces oil and sweat production, leading to dry, itchy skin. About five in 100 people in the UK are affected by hypothyroidism, more often women, and emollients can ease symptoms while hormone replacement therapy restores balance. Hyperthyroidism, though less common, can cause increased sweating and itch, and in some cases antithyroid drugs or supportive antihistamines may help.

For some, itch may be a warning sign of metabolic or systemic illness. Persistent itching around the genitals or elsewhere can signal type 2 diabetes, particularly if accompanied by thirst and urination changes. High glucose levels can predispose to thrush, a yeast overgrowth that causes genital itching. Diabetes UK notes that reducing blood sugar may alleviate itch over time. Dry skin from elevated blood sugar can also contribute to general itching.

Palms itching can point to liver disease. When the liver fails to clear bile salts from the bloodstream, these substances can deposit in the skin and trigger itch, sometimes most noticeable at night. A yellow tinge to the skin or eyes, fatigue and other symptoms warrant a liver-function test. Treatments aim to reduce bile-salt buildup and may include cholestyramine, rifampicin or, in some cases, sertraline. Kidney disease is another context in which itch is common: as kidney function declines, toxin buildup can contribute to widespread itching for roughly half of patients with advanced disease.

Unexplained generalized itching without a rash can sometimes flag iron-deficiency anaemia, which deprives tissues of oxygen and can irritate the skin. Blood tests are advised when no rash is present but itching persists. Rarely, itching can be a sign of blood cancer such as lymphoma, a condition that can be difficult to differentiate from eczema or psoriasis. Lymphoma-related itch tends to be deep, burning or stinging and may be accompanied by night sweats, fevers, fatigue, weight loss and swollen lymph nodes in the armpits, neck or groin.

Some patients experience a less common, hard-to-diagnose condition called brachioradial pruritus, which causes itch on the forearms, upper arms or neck. The cause is not fully understood, though sun exposure and nerve issues in the neck or spine are suspected. Treatments may include newer biologic drugs such as nemolizumab or older options like amitriptyline, but options remain limited and response varies by patient.

The thread running through these stories is that itching is rarely one-size-fits-all. Doctors emphasise the importance of not ignoring a persistent itch and seeking medical evaluation when it fails to respond to basic skin care. A GP can guide patients through testing for diabetes, thyroid disorders, iron deficiency and liver or kidney disease, and refer to dermatology or infectious-disease specialists if needed. Early treatment can reduce discomfort and help prevent complications.

As the stories from readers show, the emotional toll can be substantial. Patients may endure years of symptoms that disrupt sleep and daily life before a correct diagnosis is made. Health professionals urge patience and persistence in pursuit of answers, and advise those with new, persistent or worsening itch to seek medical advice rather than waiting for symptoms to improve on their own. The good news is that for many people the itch resolves once the underlying cause is identified and properly treated.