what causes skin to itch

Skin itches when certain signals from your skin and nerves tell your brain that something is irritating or damaging your body. This can be due to problems in the skin itself, internal diseases, allergies, nerve issues, or even psychological factors.
How itching actually works
Your skin and the tiny nerve endings in it are constantly âmonitoringâ the outside world. When they sense irritation, they release chemicals like histamine, which activate itch-sensitive nerves that send a message up your spinal cord to your brain. Your brain interprets this as an itch, and scratching briefly disrupts those signals, which is why it feels relieving for a moment. If the underlying cause doesnât stop, the itchâscratch cycle keeps going and can inflame the skin further.
Thatâs why an itch can go from âslightly annoyingâ to âI canât focus on anything elseâ surprisingly fast.
Common skin-related causes
These are the everyday reasons most peopleâs skin starts to itch.
- Dry skin (xerosis): Very common, especially in cold or dry weather, after hot showers, or with harsh soaps; skin may look rough or flaky and feel tight or itchy.
- Eczema (dermatitis): Inflamed, dry, often red patches that itch intensely; can be triggered by irritants, allergens, stress, or temperature changes.
- Psoriasis: Thick, scaly plaques (often on elbows, knees, scalp) that can itch or burn.
- Hives (urticaria): Raised, itchy welts that come and go, often due to allergies, infections, or medications.
- Heat rash: Small, itchy bumps when sweat ducts get blocked in hot or humid conditions.
- Insect bites and stings: Localized itchy bumps from mosquitoes, fleas, bedbugs, mites, and others.
- Fungal infections: Ringworm and other fungal rashes cause round, red, itchy patches, often in moist areas.
- Scabies and lice: Tiny parasites that live on or in the skin, causing intense itching, especially at night.
- Contact dermatitis: Itch after touching something irritating or allergenic, like certain plants (poison ivy), metals, fragrances, cosmetics, or detergents.
- Burns, scars, healing wounds: Nerves in healing tissue can fire abnormally, leading to itch.
Inside-the-body causes
Sometimes itchy skin is a signal from inside the body , not just the skinâs surface.
- Liver disease: Bile salts can build up in the body and cause widespread itching, especially on the hands and feet.
- Kidney disease: Waste buildup in the blood can cause persistent, often generalized itch.
- Thyroid problems: Both overactive and underactive thyroid can change skin texture and cause itch.
- Diabetes: Can lead to dry skin, poor circulation, and infections that all contribute to itching.
- Blood disorders and some cancers: Conditions like anemia and certain cancers (including lymphoma) can cause unexplained itching.
- Pregnancy: Hormonal changes and specific conditions like obstetric cholestasis can trigger intense itching, especially in late pregnancy.
If itch is all over , lasts weeks, and you canât see a clear cause on the skin, doctors often check for these internal issues.
Nerves, mind, and medications
Not all itch starts with a rash or an allergy.
Nerve-related causes
Damage or irritation to nerves can make them send âitchâ signals even without obvious skin problems.
- Shingles (herpes zoster): Can cause burning, pain, and itch along a nerve pathway.
- Pinched nerves, spinal problems, multiple sclerosis: Can trigger localized or unusual patterns of itch.
Psychological factors
The brain and skin are closely linked.
- Anxiety, depression, obsessive-compulsive disorder: Can make you notice sensations more, pick or scratch at skin, or even experience âphantomâ itching without a clear rash.
- âItch by suggestionâ: Seeing or hearing about itching (or reading forum threads full of people scratching!) can make you feel itchy too.
Medications and chemicals
Many everyday substances can trigger itch.
- Drugs: Opioid pain medicines, some antibiotics, and other medications can cause itching, with or without rash.
- Soaps, detergents, fragrances, wool, chemicals: These can strip oils from the skin or directly irritate it, making it dry and itchy.
When to worry and what to do
Itchy skin is usually not serious , but sometimes itâs your body asking for help.
See a doctor promptly if you notice:
- Itch that lasts more than 2â4 weeks, or keeps coming back with no clear cause.
- Intense itch all over your body, especially at night.
- Itch plus weight loss, night sweats, fevers, or severe fatigue.
- Yellow eyes/skin, very dark urine, or pale stools (possible liver issues).
- Itching in pregnancy, especially on hands and feet.
- Signs of infection in scratched areas: warmth, pus, spreading redness, or feeling generally unwell.
For mild, short-term itch, people often get relief by:
- Moisturizing regularly with fragrance-free creams or ointments.
- Using gentle, non-soap cleansers and shorter, lukewarm showers.
- Avoiding known triggers like certain fabrics, detergents, or hot environments.
- Trying over-the-counter anti-itch lotions or oral antihistamines for allergy-type itch (if safe for you).