What is the initial workup for a patient presenting with non-cancer related hair loss?

Initial Workup for Non-Cancer Related Hair Loss

For a patient presenting with hair loss, begin with a focused clinical assessment examining the pattern and characteristics of hair loss, followed by selective laboratory testing only when the diagnosis is uncertain or specific deficiencies are suspected. 1, 2

Clinical History and Physical Examination

Key Historical Elements to Obtain

• Onset, duration, and progression of hair loss—acute onset suggests telogen effluvium or alopecia areata, while gradual progression suggests androgenetic alopecia 2
• Family history of hair loss, present in approximately 20% of alopecia areata cases 1, 2
• Medication review for drugs causing anagen effluvium (chemotherapy, anticoagulants, beta-blockers) 1, 2
• Recent stressors including illness, surgery, childbirth, rapid weight loss, or emotional stress that may trigger telogen effluvium 1
• Hair care practices that might cause traction alopecia or mechanical damage 2
• Systemic symptoms suggesting autoimmune disease (thyroid dysfunction, lupus, vitiligo) 1, 2

Physical Examination Findings

• Hair pattern assessment: Diffuse thinning at the crown with frontal hairline preservation indicates androgenetic alopecia, while patchy loss suggests alopecia areata 1
• Exclamation mark hairs (short broken hairs around expanding patches) are pathognomonic for alopecia areata 1, 2
• Scalp examination for erythema, inflammation, or scaling (suggests tinea capitis or inflammatory conditions) 2
• Nail examination for pitting, ridging, or dystrophy—present in approximately 10% of alopecia areata patients 1, 2
• Lymphadenopathy assessment, particularly occipital and cervical nodes 2

Dermoscopy

Dermoscopy should be performed as a non-invasive diagnostic tool to confirm alopecia areata by identifying yellow dots, exclamation mark hairs, and cadaverized hairs 1, 2. This is particularly valuable when the clinical diagnosis is uncertain.

Laboratory Testing Approach

Laboratory testing is NOT routinely required for typical presentations of alopecia areata or androgenetic alopecia where the diagnosis is clinically evident. 3, 1, 2 However, selective testing is indicated in specific scenarios:

When to Order Laboratory Tests

Order laboratory tests when:

• The diagnosis is uncertain or presentation is atypical 3, 1
• Diffuse alopecia areata is suspected (may mimic telogen effluvium) 1, 2
• Other conditions in the differential diagnosis need exclusion 1
• Signs of systemic disease or nutritional deficiency are present 1

Recommended Laboratory Panel

When testing is indicated, order:

• Serum ferritin: Iron deficiency is the most common nutritional deficiency worldwide and a sign of chronic diffuse telogen hair loss; levels are lower in women with alopecia areata and androgenetic alopecia 1
• Vitamin D (25-OH): 70% of alopecia areata patients have deficiency (<20 ng/mL) versus 25% of controls, with lower levels correlating inversely with disease severity 1
• Thyroid stimulating hormone (TSH) and free T4: To rule out thyroid disease, which can cause hair loss 1
• Serum zinc: Levels tend to be lower in alopecia areata patients, particularly those with resistant disease >6 months duration 1

Additional Testing for Specific Clinical Scenarios

• Fungal culture: Mandatory when tinea capitis is suspected before initiating treatment 3, 1
• Skin biopsy: Indicated for difficult cases, early scarring alopecia, or diffuse alopecia areata that is challenging to diagnose 3, 1
• Serology for lupus erythematosus: When systemic lupus is in the differential diagnosis 1
• Serology for syphilis: When secondary syphilis is suspected (presents with patchy "moth-eaten" hair loss) 1

Testing for Women with Signs of Androgen Excess

In women presenting with hair loss plus acne, hirsutism, or irregular periods, consider:

• Total testosterone or bioavailable/free testosterone levels 1
• Sex hormone binding globulin (SHBG) 1
• Evaluation for polycystic ovary syndrome (PCOS) 1
• Prolactin level if hyperprolactinemia is suspected 1

Common Pitfalls to Avoid

• Ordering excessive laboratory tests when the diagnosis is clinically evident—alopecia areata is typically diagnosed clinically without laboratory workup 3, 1, 2
• Misdiagnosing diffuse alopecia areata as telogen effluvium—these can appear similar but have different prognoses 2
• Overlooking tinea capitis with subtle inflammation—fungal culture is essential before treatment 1, 2
• Failing to recognize trichotillomania—distinguished by incomplete hair loss with firmly anchored broken hairs that remain in anagen phase 1, 2
• Overlooking dermoscopy as a valuable non-invasive diagnostic tool 1
• Failing to assess psychological impact—alopecia areata may cause considerable psychological and social disability warranting assessment for anxiety and depression 1

Prognostic Considerations

• Limited disease (<25% hair loss): 68% disease-free at follow-up; 34-50% of all alopecia areata patients recover within one year without treatment 1, 2
• Extensive disease (>50% hair loss): Only 8% disease-free at follow-up; childhood onset and ophiasis pattern (scalp margin involvement) carry poorer prognoses 1, 2