22nd May 2023

Causes of iron deficiency anaemia

Iron deficiency anaemia is the most common form of anaemia worldwide. A diagnosis of iron deficiency anaemia should prompt investigation to determine the cause.

Causes of iron deficiency can be classified by mechanism:

• Iron loss
  • Gastrointestinal bleeding e.g. gastrointestinal cancer, peptic ulcer disease, ulcerative colitis, hookworm infection, Meckel’s diverticulum, haemorrhoids
  • Menorrhagia
  • Disorders of haemostasis e.g. haemophilia
  • Blood loss from haemodialysis or frequent blood donation
  • Other blood loss, e.g. haematuria, haemoptysis
• Decreased iron intake
  • Malnutrition
  • Vegan diet
• Decreased iron absorption
  • Achlorhydria e.g. secondary to atrophic gastritis
  • Inflammatory bowel disease
  • Coeliac disease
  • Gastric or duodenal surgery
• Increased requirements
  • Pregnancy and breastfeeding
  • Growth

Iron deficiency anaemia may be asymptomatic or may present with non-specific symptoms of anaemia such as pallor, lethargy, or reduced exercise tolerance. Some symptoms more specific to iron deficiency anaemia include pica (cravings for ice or non-food items) and restless legs syndrome. Physical signs on examination may include glossitis, angular cheilitis, koilonychia or brittle nails. In cases of the rare Plummer-Vinson syndrome, there may be dysphagia due to the presence of upper oesophageal webs.