The essentials

Paget's disease of bone is a chronic condition in which one or a few bones are broken down and rebuilt too fast, so they become larger but weaker. Most people have no symptoms: it is often found by chance on an X-ray or because a routine blood test shows a high alkaline phosphatase (ALP). An X-ray and a bone scan confirm it, and one infusion of a bisphosphonate usually calms it for years. This page is about the bone disease, not Paget's disease of the breast.

What is Paget's disease of bone, at a glance?

  • What happens: in the affected bones, old bone is destroyed too fast and replaced by new bone that is larger, weaker and full of blood vessels[5].
  • Other names: osteitis deformans, Paget disease of bone[5].
  • Who gets it: mostly people over 50, more often men, and people of European descent[1][8]. It affects about 1% of people over 55 in the United Kingdom, and it has become less common and milder over the past decades[1].
  • Bones most often involved: pelvis, spine, skull and leg bones[7].
  • Key tests: total ALP with liver tests in the blood, then X-rays of the painful areas and a bone scan[1][2].
  • Not the same disease: Paget disease of the breast, a cancer of the nipple, is a separate condition (see the FAQ)[12].

What are the symptoms of Paget's disease of bone?

About 70% of people with Paget's disease of bone have no symptoms at all[7]. When symptoms appear, they depend on which bones are affected and can look like ordinary arthritis[6][7].

  • Common Pain, the most frequent complaint. It can come from the bone itself or from arthritis in a nearby hip or knee[7]. The pain may be deep and present most of the time[5].
  • Possible Bowing of a leg, warm skin over the affected bone, reduced height[5].
  • Possible When the skull is involved: an enlarged head, headaches, hearing loss and dizziness[7].
  • Possible When the spine is involved: a curved back, or a narrowed spinal canal causing pain, tingling and weakness in the legs[7].
  • Rare Bone cancer (osteosarcoma), which affects less than 1% of people with the disease[7], about 0.3% in the clinical guideline[1].

Other complications include bone fractures, osteoarthritis of nearby joints, kidney stones from extra calcium, loose teeth when facial bones are involved and, in severe cases, heart failure because the heart must pump more blood to the affected bones[6].

When should I see a doctor?

When to see a doctor

  • Emergency: call 911 if, after a fall or even a small knock, you cannot put weight on a leg or a bone looks bent or out of place, or if you suddenly develop weakness or numbness in both legs or cannot walk. Pagetic bone can break, and spinal disease can press on the spinal cord[5][7].
  • Within 24 to 48 hours for a pain in an affected bone that becomes new, constant or clearly worse, or a swelling on the bone. Your doctor will check for a crack or, rarely, a tumor[1][8].
  • At your next appointment for a high ALP on a routine panel with normal liver tests, deep bone pain that lasts, a bowing leg, a hat that no longer fits, hearing loss, or a parent, brother or sister with the disease[4][6].

What causes Paget's disease of bone, and is it hereditary?

The exact cause is unknown. Researchers think it comes from a mix of genes and environment[5][7].

  • Common Family history. 12% to 40% of patients have at least one affected parent, brother, sister or child, and first-degree relatives have a 7 to 10 times higher risk[4].
  • Possible A variant in the SQSTM1 gene. It is found in up to 50% of people with a family history of the disease and up to 10% of those without one[7]. In 15% to 30% of cases, the disease is passed on in a dominant way: one altered copy of the gene is enough[7].
  • Possible Environmental triggers, such as a slow viral infection. The falling number of cases suggests a role for the environment, but no trigger has been proven[1][7].

Paget's disease of bone is different from osteoporosis: osteoporosis thins the whole skeleton slowly, while Paget's disease speeds up remodeling in a few bones only[1][7].

Which blood tests show Paget's disease of bone, and how do I read them?

The guideline from the Paget's Association, endorsed by the American Society for Bone and Mineral Research, recommends serum total ALP together with liver tests as the first blood test[1]. ALP is made both by the liver and by bone-building cells, so the liver tests help find the source. Here is a fictitious report.

Fictitious example of a lab report (United States format)
TestResultReference rangeFlag
Alkaline phosphatase (ALP)386 IU/L40-129 IU/LH
Gamma-glutamyl transferase (GGT)24 U/L5-40 U/L
Alanine aminotransferase (ALT)19 U/L4-36 U/L
Calcium, total9.6 mg/dL8.8-10.3 mg/dL
  1. ALP, flagged H: about three times the upper limit. Paget disease of bone is one of the listed causes of a high ALP, along with liver and bile duct problems, a healing fracture and other bone diseases[9].
  2. GGT and ALT, normal: GGT is measured with ALP to tell liver or bile duct disorders from bone disease[10]. A high ALP with normal liver tests points toward bone[4].
  3. Calcium, normal: Paget disease is one of the causes of a high blood calcium, and the disease is sometimes found while looking for that cause[5][11].
  4. Ranges: the ranges shown come from MedlinePlus and are examples[9][10][11]. Your laboratory's range prevails. A blood test alone does not make the diagnosis: imaging does.

A high ALP with normal liver enzymes on your report? BloodSense reads every line of your complete report, shows which results fit together and helps you prepare your questions for your doctor.

Get my full report explained

Two points matter when you read your own result. First, a normal ALP does not rule out the disease: in a population study, total ALP picked up only about 58% of cases[1], and it can stay normal when only one bone is involved[2]. If suspicion stays high, doctors can measure more specific bone markers such as bone-specific ALP, PINP or urinary NTX[1][2]. Second, a high ALP has many causes: our page on alkaline phosphatase levels explains how to tell a liver source from a bone source, and the GGT blood test page covers the liver side.

When a bone marker is high without clear symptoms, the Italian bone society first recommends routine tests such as calcium, phosphorus, kidney function, liver tests and protein electrophoresis, plus parathyroid hormone and vitamin D, before imaging[4]. They help rule out other bone diseases, such as myeloma or bone metastases[4].

How is Paget's disease of bone confirmed?

X-rays of the painful areas are the key test: the disease is almost always diagnosed with X-rays[2][6]. A radionuclide bone scan is then advised to map every active bone, because some affected bones cause no pain[1][2]. A biopsy is used only if cancer is suspected[8].

Which tests are used to follow Paget's disease over time?

After diagnosis, total ALP is the usual marker to follow the disease, with a more specific bone marker when needed[2]. A typical rhythm, suggested by the Italian bone society, is a first ALP check 3 to 6 months after treatment, then every 6 to 12 months[4]. After a zoledronic acid infusion, the same experts recommend checking blood calcium within 7 days, because calcium can drop, more often in people low in vitamin D[4].

The number is not the whole story. In the PRISM trial, aiming to normalize ALP did not give better results than treating symptoms[1], and pain can come back while ALP stays normal[1]. Report any new pain. If you have a parent or sibling with the disease, a periodic ALP check can be suggested even without symptoms[4].

How is Paget's disease of bone treated?

Not everyone needs treatment. People with no symptoms and no sign of active disease may simply be watched[5]. No doses are given here: your doctor chooses the treatment.

  • Bisphosphonates are the first treatment. They slow down bone remodeling and are recommended for bone pain caused by the disease[1][5]. A single infusion of zoledronic acid is the preferred option for most people and gives the best chance of pain relief[1][2]. Its most common side effect is a short flu-like illness[1].
  • Calcium and vitamin D: enough intake is advised during treatment, and a low vitamin D level should be corrected[4]. People with kidney stones should ask before taking supplements[6].
  • Pain relievers such as acetaminophen or anti-inflammatory drugs, and physical therapy[5][8].
  • Surgery for a fracture, a severe deformity, nerve compression, or a hip or knee replacement for arthritis[1][6]. A bisphosphonate is suggested before planned surgery on pagetic bone[2].

Experts do not fully agree on people without symptoms. The 2019 guideline found no study proving that treating them prevents complications[1]. The Endocrine Society suggests treating most people with active disease who are at risk of complications[2], for example when the skull or a weight-bearing bone is involved[5], and the Italian society suggests treating most cases at diagnosis[4]. Medicines do not repair damage already done, such as deafness or a bent bone[8].

Can Paget's disease be prevented, and how do I live with it?

There is no proven way to prevent it. In people with a family history who carry an SQSTM1 variant, genetic testing has found early silent disease, and preventive zoledronic acid favorably affected its course[3]. Most people can have a good quality of life with treatment and follow-up[8].

  • Keep your follow-up visits and blood tests, even when you feel well[4].
  • Stay active, ask which exercise is safe for your bones, and prevent falls; a cane or walker can help[6][8].
  • Have your hearing checked if your skull is involved[7].
  • Tell your relatives: your parents, brothers, sisters and children may be offered an ALP test[4].

Questions to ask your doctor

  1. Is my high ALP coming from my bones or my liver, and which test showed it?
  2. Which bones are affected, and do I need a bone scan?
  3. Do I need treatment now, or can we watch and repeat the tests?
  4. Should my vitamin D and calcium be checked before an infusion?
  5. How often should I repeat my ALP, and what change should worry me?
  6. Should my brothers, sisters or children be tested?

Frequently asked questions

Is Paget's disease of bone a type of cancer?

No. It is a disorder of bone breakdown and regrowth, not a tumor[5]. Bone cancer can develop, but rarely: in less than 1% of people with the disease[7].

Is it related to Paget's disease of the breast or nipple?

No. Paget disease of the breast is a rare cancer of the nipple and areola, making up about 1% to 3% of breast cancers[12]. It is a separate condition, diagnosed and treated in a completely different way.

Can Paget's disease spread to other bones?

No. It stays in the bones where it started and does not spread to normal bones[6][7].

How long does one zoledronic acid infusion work?

For many years in most people: bone turnover stays suppressed for more than 5 years in most patients after a single infusion[4].

  1. Ralston SH, Corral-Gudino L, Cooper C, et al. Diagnosis and management of Paget's disease of bone in adults: a clinical guideline. J Bone Miner Res. 2019;34(4):579-604. doi:10.1002/jbmr.3657 (accessed November 4, 2026)
  2. Singer FR, Bone HG, Hosking DJ, et al. Paget's disease of bone: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2014;99(12):4408-4422. doi:10.1210/jc.2014-2910 (accessed November 4, 2026)
  3. Ralston SH. Latest developments in Paget's disease of bone. Eur J Endocrinol. 2025;193(4):R43-R49. doi:10.1093/ejendo/lvaf202 (accessed November 4, 2026)
  4. Rendina D, Falchetti A, Diacinti D, et al. Diagnosis and treatment of Paget's disease of bone: position paper from the Italian Society of Osteoporosis, Mineral Metabolism and Skeletal Diseases (SIOMMMS). J Endocrinol Invest. 2024;47(6):1335-1360. doi:10.1007/s40618-024-02318-1 (accessed November 4, 2026)
  5. MedlinePlus Medical Encyclopedia. Paget disease of the bone. Reviewed October 19, 2025. US National Library of Medicine. medlineplus.gov (accessed November 4, 2026)
  6. MedlinePlus. Paget's disease of bone. US National Library of Medicine. medlineplus.gov (accessed November 4, 2026)
  7. MedlinePlus Genetics. Paget disease of bone. US National Library of Medicine. medlineplus.gov (accessed November 4, 2026)
  8. American College of Rheumatology. Paget's disease of bone. Patient fact sheet, updated February 2025. rheumatology.org (accessed November 4, 2026)
  9. MedlinePlus Medical Encyclopedia. ALP - blood test. Reviewed May 19, 2025. US National Library of Medicine. medlineplus.gov (accessed November 4, 2026)
  10. MedlinePlus Medical Encyclopedia. Gamma-glutamyl transferase (GGT) blood test. Reviewed January 1, 2025. US National Library of Medicine. medlineplus.gov (accessed November 4, 2026)
  11. MedlinePlus Medical Encyclopedia. Calcium blood test. Reviewed November 6, 2025. US National Library of Medicine. medlineplus.gov (accessed November 4, 2026)
  12. National Cancer Institute. Paget disease of the breast. Updated December 2, 2025. cancer.gov (accessed November 4, 2026)

This page is general information. It does not replace the advice of a doctor, who interprets your results with your symptoms, history, examination and imaging.