Iron Deficiency Anemia

What is iron deficiency anemia?

Iron deficiency anemia develops when body iron stores fall too low to support red cell production. It is the most common nutritional deficiency worldwide. In men and postmenopausal women it should be treated as a possible sign of gastrointestinal blood loss until proven otherwise, because it can be the first indication of bowel cancer.

Causes

• Heavy menstrual bleeding
• Gastrointestinal blood loss from ulcers, polyps or cancer
• Inadequate dietary iron
• Malabsorption from coeliac disease or after gastric surgery
• Increased demand in pregnancy and childhood growth
• Frequent blood donation

Symptoms

• Fatigue and weakness
• Pale skin and inner eyelids
• Breathlessness on exertion
• Palpitations
• Brittle nails and hair loss
• Restless legs at night
• Unusual cravings for ice or non food items
• Cracks at the corners of the mouth

Risk factors

• Heavy periods
• Pregnancy
• Vegetarian or vegan diet without planning
• Coeliac disease or inflammatory bowel disease
• Regular nonsteroidal anti inflammatory drug use
• Age over 50 with new deficiency

Diagnosis

• Full blood count showing low haemoglobin with small pale cells
• Low ferritin, the most specific marker
• Iron studies with transferrin saturation
• Coeliac serology
• Endoscopy and colonoscopy in men and postmenopausal women
• Assessment of menstrual blood loss where relevant

Treatment

• Identifying and treating the source of blood loss
• Oral iron, often alternate day dosing to improve absorption
• Taking iron with vitamin C and away from tea, coffee and calcium
• Continuing for three months after haemoglobin normalises
• Intravenous iron when oral iron fails or is not tolerated
• Transfusion only for severe symptomatic anemia

Self care

• Take iron with vitamin C and away from tea, coffee and dairy
• Consider alternate day dosing if side effects are troublesome
• Continue iron for three months after haemoglobin normalises
• Expect black stools, which are harmless
• Include haem iron sources and pair plant iron with vitamin C
• Manage constipation with fluids and fibre

When to see a doctor

Book an appointment if:

• Fatigue or breathlessness that is not improving
• Haemoglobin not rising after a month of treatment
• Iron deficiency returning after correction
• Heavy periods
• Any change in bowel habit or rectal bleeding
• Iron deficiency as a man or postmenopausal woman, which needs investigation

Some symptoms need emergency care rather than an appointment. See the warning signs listed above.

Prevention

• Eat adequate dietary iron, especially if vegetarian or vegan
• Treat heavy menstrual bleeding
• Take supplements in pregnancy as advised
• Manage coeliac and inflammatory bowel disease
• Attend bowel screening when invited
• Space blood donations appropriately

Outlook

Iron deficiency anemia corrects completely once iron is replaced and the cause is addressed. Haemoglobin usually rises within two to four weeks. The long term outlook depends entirely on the underlying cause, which is why finding the source of blood loss matters more than the supplement itself.

Related conditions

Common questions