Initial Workup for Hair Loss
For most patients presenting with hair loss, a focused clinical history and scalp examination are sufficient to establish the diagnosis without routine laboratory testing. 1
Clinical History
Obtain specific details about the hair loss pattern:
- Onset and progression: Document when hair loss began, whether it was sudden or gradual, and if it's worsening 2
- Family history: Ask about relatives with hair loss, as approximately 20% of alopecia areata cases have genetic predisposition 1, 2
- Medication review: Identify drugs that could cause anagen effluvium (chemotherapy, immunosuppressants) 1, 2
- Hair care practices: Inquire about tight hairstyles, chemical treatments, or pulling behaviors that suggest traction alopecia or trichotillomania 2
- Systemic symptoms: Screen for signs of autoimmune disease, thyroid dysfunction, or nutritional deficiencies 1, 2
Physical Examination
Perform a systematic scalp assessment:
- Pattern recognition: Determine if hair loss is patchy, diffuse, or follows a specific distribution 2, 3
- Scalp inflammation: Look for erythema, scaling, or pustules that suggest tinea capitis or scarring alopecia 1, 2
- Exclamation mark hairs: Identify short broken hairs with tapered roots characteristic of alopecia areata 1, 2
- Hair pull test: Gently pull 50-60 hairs; more than 6 hairs removed suggests active shedding 3
- Nail examination: Check for pitting or dystrophy, present in 10% of alopecia areata patients 2
- Lymph nodes: Palpate occipital and cervical nodes for lymphadenopathy 2
Dermoscopy
Use dermoscopy to confirm the diagnosis and differentiate between conditions:
- Alopecia areata: Yellow dots, exclamation mark hairs, and cadaverized hairs (fractured before emergence) 1, 2
- Androgenetic alopecia: Hair diameter diversity and peripilar signs 4
- Tinea capitis: Comma hairs and broken hairs with irregular borders 4
Laboratory Testing
Investigations are unnecessary in most cases of typical alopecia areata. 1, 2
When the diagnosis is uncertain, consider:
- Fungal culture: For suspected tinea capitis with scalp scaling 1
- Skin biopsy: Essential for all cicatricial alopecias and diagnostically challenging cases 1, 3, 4
- Lupus serology: If systemic lupus erythematosus is suspected 1
- Syphilis serology: For secondary syphilis in the differential 1
Important caveat: Routine screening for thyroid disease, iron deficiency, or other autoimmune conditions is not recommended for typical alopecia areata, despite increased frequency of these conditions in affected patients. 1 The British Association of Dermatologists specifically notes that iron deficiency testing is not recommended, as subsequent studies failed to confirm initial findings and no treatment response to iron replacement has been demonstrated. 1
Differential Diagnosis Pitfalls
Avoid these common diagnostic errors:
- Trichotillomania vs. alopecia areata: In trichotillomania, broken hairs remain firmly anchored in anagen phase, unlike exclamation mark hairs that pull out easily 1, 2
- Diffuse alopecia areata vs. telogen effluvium: Diffuse alopecia areata can mimic telogen effluvium; dermoscopy and clinical course help differentiate 1, 2
- Tinea capitis with subtle signs: Inflammation and scaling may be minimal; maintain high suspicion and perform fungal culture 1, 2
- Early scarring alopecia: May present without obvious scarring initially; biopsy is essential when suspected 1
Prognostic Indicators
Document extent of hair loss for prognostic purposes:
- Patients with <25% initial hair loss have 68% disease-free rate at follow-up 2
- Patients with >50% initial hair loss have only 8% disease-free rate at follow-up 2
- Duration <1 year with limited patchy loss has up to 80% spontaneous remission rate 1
When to Refer
Consider dermatology referral for: