Itching All Over the Body: Causes, When to Worry and Which Blood Tests Help
The essentials
Itching all over the body usually comes from the skin itself: dry skin, eczema, hives, mites or a new medicine. When the skin looks normal and the itch lasts more than 6 weeks, a few blood tests check the liver, kidneys, thyroid, iron and blood cells. Itching with hives and trouble breathing is an emergency.
About 1 in 5 people has long-lasting itch at some point in life, and about 7% develop it in a given year[1]. It is called chronic after 6 weeks[1]. The first question: is there a rash, or does the skin look normal? Among people sent to a dermatologist for whole-body itching with no skin cause, 14 to 24% turn out to have an illness elsewhere in the body[2].
When is itching all over the body an emergency?
When to see a doctor
- Emergency: call 911 if itching or hives come with trouble breathing, swelling of the face, lips or tongue, or fainting: possible anaphylaxis, a severe allergic reaction[7].
- Within 24 to 48 hours for itching with yellow skin or eyes, dark urine or pale stools, or belly pain[3]; itching in pregnancy, especially on the palms and soles[8]; or itching with weight loss, night sweats or fever[2][3].
- At your next appointment for itching all over the body that lasts despite moisturizer, keeps you awake or has no clear cause[4][5].
Why do I itch all over? Skin causes first
- Common Dry skin. Often worse in winter and with age, mostly on the back, sides, belly and legs[2]. Hot showers and perfumed soaps make it worse[5].
- Common Skin conditions. Eczema, psoriasis, hives, allergic and irritant reactions to soaps, wool or metals[4][6].
- Common Mites and insects. Scabies mites, lice and bedbugs can cause a long-lasting, intense itch[6].
- Common Medicines. Opioids, aspirin, some antibiotics, ACE inhibitors (blood pressure pills) and statins can cause itching, even months after starting them[3][4][6]. Never stop a medicine without asking the prescriber.
- Common Pregnancy and menopause. Mild itching is common in both[5].
Which illnesses cause itching all over the body without a rash?
- Possible Kidney disease. About 20% of people with chronic kidney disease and 40% of those with kidney failure itch[9], often on the back, arms and legs[6].
- Possible Liver and bile duct disease. Hepatitis, cirrhosis or a blocked bile duct; the itch often starts on the palms and soles and then spreads[6], and it can come years before some bile duct diseases are diagnosed[1]. See hepatitis and its blood tests.
- Possible Iron deficiency. Low iron stores are linked to long-lasting itch, although the reason is not known[1][4]. See iron deficiency symptoms and tests.
- Possible Thyroid disease and diabetes. Both an overactive and an underactive thyroid can cause itch; diabetes is suggested by thirst, frequent urination and weight loss[3][6].
- Possible Cholestasis of pregnancy. A liver condition that affects about 7 in 1,000 pregnant women in the UK: itching without a rash, usually after 28 weeks, often on the palms and soles and worse at night[8].
- Rare Blood disorders. In polycythemia vera, a bone marrow disease that makes too many red cells, 301 of 441 patients had itching after contact with water, such as a shower; in most of them it came on years before the diagnosis[10]. Itching affects up to 30% of people with Hodgkin lymphoma[2].
- Rare Other causes. HIV, nerve diseases and, once all else is ruled out, psychological causes[1][3].
What blood tests check for causes of itching all over the body?
When the skin does not explain the itch, European and US guidance suggest a similar first round of tests[1][2].
| Test | What it answers | Usually when |
|---|---|---|
| Complete blood count with differential | Anemia, too many red cells, high eosinophils? | Almost always |
| Ferritin | Are iron stores low? | Almost always |
| Creatinine, BUN and eGFR | Do the kidneys filter well? | Almost always |
| Liver tests: ALT, AST, ALP, GGT, bilirubin | Is the liver or bile flow involved? | Almost always |
| TSH | Is the thyroid involved? | Almost always |
| Glucose or HbA1c | Is there diabetes? | Almost always |
| ESR, CRP, LDH | Hidden inflammation or a blood disease? | Often in the first round |
| Bile acids with liver tests | Cholestasis of pregnancy? | Itching in pregnancy |
| HIV and hepatitis tests, chest X-ray | Infection or lymphoma? | Depending on history |
Kidney and liver tests come together in a comprehensive metabolic panel.
BloodSense explains your whole report line by line, in plain words, so you know which result may matter for the itch.
Explain my resultsHow do I read my results?
| Test | Result | Reference range | Flag |
|---|---|---|---|
| Hemoglobin | 11.2 g/dL | 12.1-15.1 g/dL | L |
| MCV | 76 fL | 79-95 fL | L |
| Ferritin | 8 ng/mL | 13-150 ng/mL | L |
| Creatinine | 0.8 mg/dL | 0.5-0.95 mg/dL | |
| Alkaline phosphatase (ALP) | 88 U/L | 40-129 U/L | |
| TSH | 1.9 mIU/L | 0.4-4.8 mIU/L |
- L means below this lab's range: mild anemia with small red cells (low MCV)[12].
- Ferritin is the iron store. At 8 ng/mL it is very low: iron deficiency is the likely link, and the doctor will look for why iron is lost (heavy periods, bleeding in the gut)[1][12].
- Kidney, bile flow (ALP) and thyroid are normal[12].
Blood count and ferritin
A high hemoglobin and hematocrit leads to tests for polycythemia vera (erythropoietin, JAK2 gene). High eosinophils lead to a stool test for parasites[1]; see eosinophils. The lower the ferritin, even inside the normal range, the more likely iron stores are short[12].
Kidney and liver tests
A high creatinine with a low eGFR points to the kidneys; next come calcium, phosphate, parathyroid hormone and a urine test[1]. A high ALP can come from blocked bile ducts, liver disease or bone[12]; a raised GGT at the same time points to the liver. Abnormal liver tests lead to hepatitis tests and a liver ultrasound[1]. In pregnancy, bile acids can be high even with normal liver tests; both are repeated if the itch goes on[8].
Everything is normal
Then the skin, dryness or a medicine remain the likely causes. If the itch lasts, tests can be repeated and a dermatologist can look for subtle skin disease[1][6].
What should I note before the appointment?
- When and where the itch started; worse at night?
- Rash or normal skin; does anyone at home itch?
- Itch after a shower, or on the palms and soles
- All medicines and supplements, with start dates
- Weight loss, night sweats, fever, thirst, yellow eyes, dark urine; pregnancy
Questions to ask your doctor
- Could one of my medicines be causing the itch?
- If my ferritin or liver tests are abnormal, what is the next step?
- When should the tests be repeated if I still itch?
Frequently asked questions
Is itching all over the body a sign of cancer?
Rarely. In 8,744 people with chronic itch, the overall 5-year cancer risk was not clearly higher; blood and bile duct cancers were somewhat more frequent but stayed very uncommon[11].
Can itching be the only sign of a liver or kidney problem?
Yes. Itch can be the only symptom of some liver, kidney and blood diseases, which is why the blood tests above are useful when the skin looks normal[6].
Can stress make me itch all over?
Stress can worsen any itch, and some itch has a psychological origin. But doctors only conclude this after the skin and blood tests have ruled out other causes[1][3].
Related tests and guides
- Iron deficiencySymptoms, causes and the blood tests that confirm it.
- High liver enzymesWhat raised ALT and AST mean and what comes next.
- eGFR blood testHow to read your kidney filtration number.
- Complete blood countRed cells, white cells and platelets, line by line.
References
- Weisshaar E, Szepietowski JC, Dalgard FJ, et al. European S2k guideline on chronic pruritus. Acta Derm Venereol. 2019;99(5):469-506. doi:10.2340/00015555-3164 (accessed November 10, 2026)
- Reamy BV, Bunt CW, Fletcher S. A diagnostic approach to pruritus. Am Fam Physician. 2011;84(2):195-202. aafp.org (accessed November 10, 2026)
- MSD Manual Professional Version. Pruritus. msdmanuals.com (accessed November 10, 2026)
- MedlinePlus Medical Encyclopedia. Itching. medlineplus.gov (accessed November 10, 2026)
- NHS. Itchy skin. nhs.uk (accessed November 10, 2026)
- American Academy of Dermatology. 10 reasons your skin itches uncontrollably and how to get relief. aad.org (accessed November 10, 2026)
- MedlinePlus Medical Encyclopedia. Anaphylaxis. medlineplus.gov (accessed November 10, 2026)
- Royal College of Obstetricians and Gynaecologists. Intrahepatic cholestasis of pregnancy (patient information, based on Green-top Guideline No. 43, 2022). rcog.org.uk (accessed November 10, 2026)
- Verduzco HA, Shirazian S. CKD-associated pruritus: new insights into diagnosis, pathogenesis, and management. Kidney Int Rep. 2020;5(9):1387-1402. doi:10.1016/j.ekir.2020.04.027 (accessed November 10, 2026)
- Siegel FP, Tauscher J, Petrides PE. Aquagenic pruritus in polycythemia vera: characteristics and influence on quality of life in 441 patients. Am J Hematol. 2013;88(8):665-669. doi:10.1002/ajh.23474 (accessed November 10, 2026)
- Fett N, Haynes K, Propert KJ, Margolis DJ. Five-year malignancy incidence in patients with chronic pruritus: a population-based cohort study aimed at limiting unnecessary screening practices. J Am Acad Dermatol. 2014;70(4):651-658. doi:10.1016/j.jaad.2013.11.045 (accessed November 10, 2026)
- MedlinePlus Medical Encyclopedia. Normal ranges: ferritin, hemoglobin, RBC indices, ALP, creatinine, TSH (accessed November 10, 2026)
This article is general health information. It does not replace a medical examination, diagnosis or treatment. Do not stop a medicine or start iron tablets without talking to your doctor.
