How do I determine if I have female pattern hair loss and a potential nutrition deficiency or iron deficiency anemia?

Determining Female Pattern Hair Loss vs. Nutritional Deficiency/Anemia

You need to distinguish female pattern hair loss (FPHL) from nutritional causes through clinical pattern recognition and targeted laboratory testing, though these conditions can coexist and nutritional deficiencies are NOT more common in FPHL patients than in the general population. 1

Clinical Pattern Recognition

Female Pattern Hair Loss Characteristics

• Hair loss pattern: Centrifugal expansion in the mid-scalp (widening part) OR frontal accentuation in a "Christmas tree" pattern, with the frontal hairline typically preserved 2
• Onset: Gradual progression over months to years 2
• Hair quality: Progressive miniaturization of hair follicles, with terminal hairs converting to thinner, shorter intermediate hairs 3

Nutritional Deficiency Hair Loss Characteristics

• Hair loss pattern: Diffuse thinning across the entire scalp (chronic telogen effluvium pattern), NOT the characteristic mid-scalp or frontal patterns of FPHL 4, 2
• Onset: Develops gradually over months with iron deficiency 5
• Associated symptoms: May have fatigue, pallor, brittle nails, or other systemic signs of anemia 4

Essential Laboratory Testing

Order these tests for any woman presenting with hair loss: 6

First-Line Tests

• Complete blood count (CBC): Assess hemoglobin, mean corpuscular volume (MCV), and red blood cell indices to detect anemia 6
• Serum ferritin: The single most important test for iron stores; ferritin ≤15 μg/L confirms iron deficiency with 98% specificity in premenopausal women 6
• Thyroid-stimulating hormone (TSH): Rule out thyroid dysfunction 6, 2
• Transferrin saturation: Less affected by inflammation than ferritin and provides additional iron status information 6

Additional Recommended Tests

• Vitamin D level: Optional but recommended in FPHL evaluation 2
• Zinc level: Optional but recommended 2
• Prolactin: Optional but recommended 2
• Androgen levels: Mandatory assessment in all FPHL patients to evaluate for hyperandrogenism 2

Critical Interpretation Pitfalls

Ferritin Interpretation Challenges

• False elevation: Ferritin can be falsely elevated during infection, inflammation, or chronic disease, potentially masking true iron deficiency 6, 4
• "Normal" ferritin with iron deficiency: If ferritin is 15-60 ng/mL but you have microcytic anemia or low MCV, iron deficiency may still be present 6
• Solution: Check transferrin saturation and serum iron/total iron-binding capacity (TIBC) when ferritin appears normal but clinical suspicion remains high 6

Evidence Regarding Iron Deficiency in FPHL

The relationship between iron deficiency and FPHL is controversial and NOT clearly established: 1

• A controlled study of 381 women found NO statistically significant increase in iron deficiency in premenopausal or postmenopausal women with FPHL compared to controls 1
• When using ferritin ≤15 μg/L as the definition, iron deficiency occurred in only 12.4% of premenopausal FPHL patients versus 29.8% of controls 1
• However, the British Association of Dermatologists states that routine testing for iron status is NOT recommended in alopecia areata, as studies have not confirmed increased iron deficiency 7

Practical Diagnostic Algorithm

Step 1: Clinical Assessment

• Examine the pattern of hair loss (mid-scalp widening vs. diffuse thinning) 2
• Look for signs of systemic illness, anemia symptoms, or hyperandrogenism 4, 2
• Obtain menstrual history and assess for risk factors for blood loss 4

Step 2: Laboratory Workup

• Order CBC, ferritin, TSH, and transferrin saturation as baseline 6
• If ferritin is 15-60 ng/mL with microcytic anemia, add serum iron and TIBC 6
• Consider androgen panel if FPHL pattern is present 2

Step 3: Identify Underlying Causes

• If iron deficiency is confirmed: Investigate the source, especially gastrointestinal blood loss in men and postmenopausal women, or menstrual blood loss in premenopausal women 4
• If unexplained iron deficiency: Check tissue transglutaminase (TTG) antibodies to rule out celiac disease 6

Step 4: Interpretation

• FPHL with normal labs: Isolated FPHL should NOT be considered a sign of hyperandrogenism when androgen levels are normal 2
• Iron deficiency without FPHL pattern: Likely chronic telogen effluvium from nutritional deficiency 5, 4
• Both conditions can coexist: Treat both if present 4

Important Clinical Considerations

Treatment Implications

• Iron deficiency anemia should be treated regardless of hair loss type 4
• Treating iron deficiency without anemia is controversial: There is insufficient evidence to recommend iron supplementation for hair loss patients with iron deficiency but no anemia 4
• Cleveland Clinic practice: Screen all patients with hair loss for iron deficiency and treat when found, though this is not strictly evidence-based 4
• Iron supplementation timing: May result in better prognosis when started within 6 months of onset 5

Avoid These Pitfalls

• Do not assume all hair loss is nutritional: Iron deficiency is NOT more common in FPHL patients than in the general population 1
• Do not over-supplement iron: Excessive iron can cause iron overload, especially in patients with hereditary hemochromatosis 4
• Do not rely solely on ferritin: Use transferrin saturation and CBC to confirm iron status when ferritin is equivocal 6