What is the treatment approach for a patient with hair loss and potentially low ferritin levels, indicating iron deficiency?

Treatment Approach for Hair Loss with Low Ferritin

Check serum ferritin in all patients with chronic hair loss, and treat iron deficiency (ferritin ≤15 μg/L) even without anemia, as early supplementation within 6 months of onset improves prognosis. 1, 2

Initial Diagnostic Workup

Order these specific tests for every patient with hair loss:

• Serum ferritin - the single most important test to assess iron stores 1, 3
• Complete blood count (CBC) to evaluate hemoglobin, MCV, and red cell indices 1
• Thyroid-stimulating hormone (TSH) 1, 2
• Transferrin saturation (calculated from serum iron and total iron-binding capacity) 1
• Consider tissue transglutaminase (TTG) antibodies if unexplained iron deficiency is found, to rule out celiac disease 1, 2

Interpreting Ferritin Results

Critical thresholds and interpretation pitfalls:

• Ferritin ≤15 μg/L confirms iron deficiency with 98% specificity in premenopausal women 4, 1, 2
• Without inflammation, ferritin <30 μg/L or transferrin saturation <16% defines iron deficiency 2
• Ferritin can be falsely elevated during infection, inflammation, chronic disease, malignancy, or liver damage, potentially masking true iron deficiency 4, 1, 2
• If ferritin appears "normal" (15-60 ng/mL) but you have microcytic anemia or low MCV, iron deficiency may still be present 1
• With inflammation present, the lower limit of normal ferritin increases to 100 μg/L, as ferritin is an acute-phase reactant 2

Always assess inflammatory markers (CRP, ESR) alongside ferritin to aid proper interpretation 2

When Ferritin Appears Normal But Iron Deficiency Is Suspected

If ferritin is in the 15-60 ng/mL range but clinical suspicion remains high:

• Check transferrin saturation and serum iron/TIBC to confirm iron status 1
• Transferrin saturation is less affected by inflammation than ferritin and may be more reliable in inflammatory conditions 1
• Recent evidence suggests ferritin ≥60 ng/mL (corresponding to hemoglobin ≥13.0 g/dL) may be the optimal threshold for adequate hair growth 5

Treatment Recommendations

Treat iron deficiency even without anemia in the context of hair loss:

• The American Academy of Dermatology and Cleveland Clinic Foundation practice patterns support treating iron deficiency without anemia (ferritin ≤15 μg/L, normal hemoglobin) specifically for hair loss 2, 6
• Iron supplementation started within 6 months of hair loss onset results in better prognosis 2, 5
• Hair loss due to iron deficiency develops gradually over months, not acutely 3, 2

Specific iron supplementation regimen:

• Ferrous sulfate 324 mg tablets contain 65 mg of elemental iron, providing 362% of the U.S. recommended daily intake 7
• Continue supplementation until ferritin levels normalize and monitor every 3 months 5
• Patients with subjective improvement of hair regrowth show greater increases in ferritin levels after supplementation 5

Evidence Quality and Nuances

The relationship between iron deficiency and hair loss varies by type:

• Multiple studies found lower ferritin levels in patients with diffuse hair loss, telogen effluvium, and androgenetic alopecia 3, 2, 6
• For alopecia areata specifically, evidence is conflicting - only 2 of 8 studies supported an association, with the discrepancy appearing related to sex differences (studies supporting the association were primarily in female subjects) 4, 2
• The British Association of Dermatologists states routine iron testing is not recommended for alopecia areata 2
• One study found no direct relationship between low serum ferritin (≤20 μg/L) and chronic diffuse telogen hair loss, with iron supplementation alone failing to reverse hair loss in 5 women with normal scalp histology 8

Common pitfalls to avoid:

• Do not rely on ferritin alone if inflammatory conditions are present 4, 1, 2
• Avoid excessive iron supplementation, which can cause iron overload, especially in high-risk patients such as those with hereditary hemochromatosis 6
• Disease duration is an important prognostic factor - initiation of treatment within 6 months yields better outcomes 2, 5
• If patients do not respond to iron replacement therapy, investigate other underlying causes of iron deficiency or hair loss 6

Identifying the Cause of Iron Deficiency

Once iron deficiency is confirmed, identify the underlying cause:

• In premenopausal women: menstrual blood loss and pregnancy are most common 6
• In men and postmenopausal women: evaluate for gastrointestinal blood loss and malabsorption 6
• If the patient is male, postmenopausal female, or has risk factors for blood loss, evaluate for sources of blood loss, especially gastrointestinal (e.g., colon cancer) 6