Medical Investigations for Hair Loss

When Are Hair Loss Investigations Considered?

Investigations may be useful when hair loss is:

• Sudden or unexplained
• Diffuse rather than patterned
• Associated with fatigue or other symptoms
• Occurring after illness or major physiological stress
• Associated with dietary restriction or weight loss
• Accompanied by menstrual or hormonal changes
• Not typical of straightforward pattern hair loss

What Tests May Be Considered?

Depending on the history and examination, investigations may include:

• Full blood examination
• Iron studies and ferritin
• Thyroid function tests
• Vitamin B12 or folate where indicated
• Vitamin D where clinically appropriate
• Zinc or other nutritional testing in selected cases
• Hormonal testing when clinically relevant
• Other tests based on symptoms and medical history

Not every patient needs blood tests, and no single test explains every type of hair loss.

Why Is Medical History Important?

Laboratory testing should be interpreted alongside:

• Pattern and duration of hair loss
• Medical conditions
• Medication use
• Diet and nutrition
• Recent illness
• Weight change
• Pregnancy or postpartum history where relevant
• Menstrual or hormonal history where relevant
• Scalp examination
• Trichoscopy findings

What Happens After the Results?

Results are reviewed together with the clinical findings. Depending on the outcome, management may include:

• Correction of an identified deficiency
• Treatment of an underlying medical condition
• Hair-loss treatment
• Further investigation
• Monitoring
• Referral to another specialist where required

Correcting a deficiency does not always restore hair, and response varies between individuals.