Itchy Skin: Causes and How to Stop the Itch

Why skin itches

Itch is carried by specialized nerve fibers in the skin. Histamine from allergic cells, inflammatory chemicals in eczema, dry and cracked skin, and substances that build up in the blood in liver or kidney disease all activate these nerves. Scratching briefly relieves itch by causing mild pain, but it damages the skin, releasing more inflammatory chemicals and starting an itch-scratch cycle.

Itchy skin with a rash

Itchy skin without a rash

When itching has no visible cause apart from scratch marks, doctors look for internal reasons:

• Dry skin (xerosis): the most common cause, especially in older adults and in winter. Skin looks dull and fine-lined.
• Medicines: opioids, some blood pressure medicines, statins, and allergic reactions to many drugs.
• Liver disease: blockage of bile flow, primary biliary cholangitis and hepatitis. Itch is often worst on the palms and soles and at night. See liver disease.
• Chronic kidney disease: itching is common in advanced disease and on dialysis.
• Thyroid disease: both overactive and underactive thyroid.
• Iron deficiency and polycythemia vera, in which itching after a warm bath is typical.
• Lymphoma: persistent itch with night sweats, fevers, weight loss or swollen nodes.
• Diabetes: mostly through dry skin and infections.
• Nerve-related itch: a localized itch, for example between the shoulder blades (notalgia paresthetica) or on the outer arms in sunny climates.
• Pregnancy: mild itch is common. Intense itching of palms and soles in the third trimester can be intrahepatic cholestasis of pregnancy, which needs blood tests.
• Anxiety and stress can intensify itch, but should be considered only after physical causes are ruled out.

Red, itchy skin on the scrotum or groin

A red, itchy, warm rash on the scrotum or inner thighs is common and usually caused by:

• Jock itch (tinea cruris): a fungal infection with a red, scaly, spreading edge on the inner thighs. It often spares the scrotum itself.
• Candida (yeast) infection: bright red, moist skin that does involve the scrotum, with small red "satellite" spots. More common with diabetes, obesity and after antibiotics.
• Intertrigo: irritation from skin rubbing on skin, heat and sweat, causing raw, red, warm skin in folds.
• Contact dermatitis from soaps, laundry detergent, condoms or creams.
• Eczema, psoriasis or lichen simplex (thickened skin from chronic scratching).
• Scabies or pubic lice: intensely itchy bumps, especially at night.

Keeping the area clean and dry, wearing loose cotton underwear, and using an over-the-counter antifungal cream (clotrimazole or terbinafine) for 2 to 4 weeks clears most fungal causes. See a doctor if it does not improve in 2 weeks, if there are sores or blisters, or if a sexually transmitted infection is possible.

Itchy skin at night

Itch often feels worse at night because body temperature rises, the skin loses more water, and there are fewer distractions. Scabies, eczema, liver disease and dry skin are classic causes of night itch. Keep the bedroom cool, moisturize before bed and use cotton bedding.

How doctors find the cause

The doctor will ask where and when you itch, how long, new products, medicines, travel, pets, and whether others at home itch. They will examine your skin, nails, scalp and lymph nodes. Tests may include:

• skin scraping for scabies or fungus
• patch testing for contact allergies
• blood tests: blood count, iron, liver and kidney function, thyroid, blood sugar
• skin biopsy for unusual rashes

Itchy skin relief

• Moisturize at least twice a day with a thick, fragrance-free cream or ointment, especially within 3 minutes of bathing.
• Shower or bathe in lukewarm water, not hot, for under 10 minutes. Use a gentle, soap-free cleanser.
• Cool the skin: a cool, damp cloth for 5 to 10 minutes, or a cooling lotion containing menthol or calamine.
• Avoid scratching: keep nails short, pat or press the skin instead, and wear cotton gloves at night if needed.
• Wear loose, soft clothing made of cotton. Avoid wool and rough fabrics.
• Use fragrance-free laundry detergent and skip fabric softener.
• Humidify dry indoor air in winter.
• Short-term over-the-counter options: 1% hydrocortisone cream for small patches of eczema or bites (not on broken or infected skin, or for long periods on the face or groin), and non-drowsy antihistamines for hives. Sedating antihistamines may help sleep but are not recommended for older adults.

Prescription treatments depend on the cause: stronger steroid creams, antifungals, scabies treatment for the whole household, and specific medicines for liver- or kidney-related itch.

Frequently asked questions

Why is my skin itchy with no rash?

The most common reason is dry skin. Other causes include medicines, liver or kidney disease, thyroid problems, iron deficiency, pregnancy and, rarely, lymphoma. If itching lasts more than 2 weeks despite moisturizing, see a doctor for blood tests.

What causes red, itchy skin on the scrotum with a warm feeling?

Usually a yeast (candida) infection, a fungal infection (jock itch), intertrigo from heat and friction, or contact dermatitis from soaps or laundry products. Keeping the area dry and using an antifungal cream helps most cases. See a doctor if it persists beyond 2 weeks or there are sores.

Why does my skin itch more at night?

At night your skin is warmer, loses more moisture and your body releases fewer anti-inflammatory hormones, while there are fewer distractions. Scabies, eczema and liver-related itch are typically worse at night.

When should I see a doctor for itchy skin?

See a doctor if itching lasts more than 2 weeks, is severe, affects your whole body, keeps you awake, or comes with weight loss, fever, night sweats, yellow skin or tiredness. Get emergency help for itching with swelling of the face or trouble breathing.