Last reviewed: 23 Sep 2021
Last updated: 21 Aug 2019



History and exam

Key diagnostic factors

  • presence of risk factors
  • bowing of the legs
  • widening of the ends of the long bones
  • delayed tooth eruption and early dental caries
  • chest deformity
  • throbbing, aching bone discomfort and/or irritability
  • head sweating
  • localised or generalised bone tenderness
  • proximal muscle weakness
  • rachitic rosary
  • frontal bossing
  • waddling gait

Other diagnostic factors

  • failure to thrive
  • delayed achievement of motor milestones
  • fatigue and malaise
  • symptoms of hypocalcaemia

Risk factors

  • inadequate sunlight exposure
  • increased skin pigmentation
  • age >50 years
  • inadequate dietary and supplemental vitamin D intake
  • malabsorption
  • obesity
  • medication use
  • genetic mutations
  • tumour
  • chronic kidney disease
  • granulomatous disorders
  • primary hyperparathyroidism
  • hyperthyroidism

Diagnostic investigations

1st investigations to order

  • serum 25-hydroxyvitamin D
  • serum alkaline phosphatase
  • serum calcium
  • fasting serum phosphate
  • plain-film radiographs of knees and wrists

Investigations to consider

  • intact PTH
  • serum 1,25-dihydroxyvitamin D
  • bone density (DEXA) scan

Treatment algorithm



Michael F. Holick, PhD, MD

Director Bone Healthcare Clinic

Director Ehlers-Danlos Clinical Research Programme

Professor of Medicine, Physiology, and Biophysics

Departments of Medicine, Physiology, and Biophysics

Section of Endocrinology, Diabetes, and Nutrition

Vitamin D, Skin, and Bone Research Laboratory

Boston University School of Medicine




MFH is a consultant for Quest Diagnostics and a speaker for Abbott. He also chaired the Endocrine Society’s practice guidelines on vitamin D. MFH is an author of references cited in this topic.

Peer reviewers

Vin Tangpricha, PhD, MD

Professor of Medicine

Division of Endocrinology

Metabolism and Lipids

Emory University School of Medicine




VT is an author of references cited in this topic.

Stefan Pilz, MD

General Practitioner

Resident at the Department of Internal Medicine

Division of Endocrinology and Nuclear Medicine

Medical University of Graz




SP is an author of references cited in this topic.

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