What are the initial laboratory tests and interventions for a patient presenting with alopecia, headache, feeling warm, and nocturnal sweating?

Initial Laboratory Workup for Alopecia with Constitutional Symptoms

For a patient presenting with alopecia, headache, feeling warm, and night sweats, immediately check TSH, complete blood count, ESR/CRP, and consider syphilis serology, as these constitutional symptoms suggest systemic disease rather than isolated alopecia areata. 1, 2

Critical Distinction: Isolated Alopecia vs. Systemic Presentation

The combination of alopecia with headache, warmth sensation, and night sweats is not typical for primary alopecia areata and warrants investigation for systemic conditions. 1, 2

Constitutional Symptoms Require Expanded Workup

• Night sweats, fever sensation, and headache suggest possible systemic lupus erythematosus, secondary syphilis, thyroid disease, or other systemic conditions that can present with hair loss. 1, 2
• The British Journal of Dermatology specifically recommends lupus serology when systemic lupus is in the differential diagnosis, and syphilis serology when secondary syphilis is suspected—both can present with patchy hair loss and constitutional symptoms. 1

Essential Initial Laboratory Tests

Mandatory First-Line Tests

• Thyroid function (TSH) to rule out thyroid disease, which causes hair loss and can present with temperature dysregulation and headaches. 1
• Complete blood count to evaluate for anemia, infection, or hematologic abnormalities that could explain constitutional symptoms. 1, 2
• Inflammatory markers (ESR/CRP) to assess for systemic inflammation suggesting autoimmune or infectious processes. 1, 2
• Syphilis serology given that secondary syphilis presents with patchy "moth-eaten" hair loss and systemic symptoms including fever and malaise. 1

Secondary Tests Based on Clinical Presentation

• Lupus serology (ANA, anti-dsDNA) if systemic lupus erythematosus is suspected, as it causes both scarring and non-scarring alopecia with constitutional symptoms. 1
• Serum ferritin since iron deficiency is the most common nutritional deficiency worldwide and causes chronic diffuse telogen hair loss, though less likely to explain constitutional symptoms. 1
• Vitamin D level as 70% of alopecia areata patients have deficiency (<20 ng/mL) versus 25% of controls, with inverse correlation to disease severity. 1

Diagnostic Algorithm

Step 1: Examine the Scalp Pattern

• Patchy hair loss with exclamation mark hairs (short broken hairs around expanding patches) indicates alopecia areata. 1, 2
• Diffuse thinning at crown with frontal hairline preservation suggests androgenetic alopecia in women. 1
• Scalp inflammation, scaling, or pustules requires fungal culture to rule out tinea capitis. 1

Step 2: Perform Dermoscopy

• Yellow dots, exclamation mark hairs, and cadaverized hairs are pathognomonic for alopecia areata. 1
• Dermoscopy is the single most useful non-invasive tool to differentiate diffuse alopecia areata, telogen effluvium, and androgenetic alopecia. 1

Step 3: Targeted Laboratory Testing

• If constitutional symptoms present: Prioritize TSH, CBC, ESR/CRP, syphilis serology, and lupus serology over nutritional testing. 1, 2
• If isolated alopecia areata with typical dermoscopic findings: The British Journal of Dermatology states investigations are unnecessary in most cases, as diagnosis is made clinically. 1
• If diagnosis uncertain or atypical presentation: Consider skin biopsy for definitive histopathologic diagnosis. 1

Additional Hormonal Testing (If Indicated)

• Total testosterone, free testosterone, and SHBG in women with signs of androgen excess (acne, hirsutism, irregular periods). 1
• Prolactin level if hyperprolactinemia suspected. 1
• Two-hour oral glucose tolerance test if PCOS, diabetes, or insulin resistance suspected. 1

Common Pitfalls to Avoid

• Ordering excessive laboratory tests when diagnosis is clinically evident—most alopecia areata is diagnosed clinically without workup. 1
• Failing to recognize that constitutional symptoms mandate systemic investigation—isolated alopecia areata does not typically present with night sweats, fever sensation, and headaches. 1, 2
• Missing secondary syphilis, which presents with patchy hair loss and systemic symptoms including fever, malaise, and lymphadenopathy. 1
• Overlooking thyroid disease, which can cause both hair loss and temperature dysregulation. 1
• Neglecting psychological assessment, as alopecia causes considerable psychological and social disability warranting screening for anxiety and depression. 1

When to Consider Biopsy

• Diffuse alopecia areata that is diagnostically challenging may require histopathologic confirmation. 1
• Early scarring alopecia or when systemic conditions like lupus are suspected. 1
• Diagnosis remains uncertain after dermoscopy and initial laboratory testing. 1