From the Guidelines
Laboratory tests are not recommended for most cases of alopecia areata.
Recommended Tests
When the diagnosis is in doubt, the following tests may be considered:
- Fungal culture
- Skin biopsy
- Serology for lupus erythematosus
- Serology for syphilis 1 It is not recommended to routinely test for iron status, as there is no evidence to support a treatment response to iron replacement therapy in patients with alopecia areata 1.
Rationale
The British Association of Dermatologists' guidelines for the management of alopecia areata suggest that investigations are unnecessary in most cases, and that the increased frequency of autoimmune disease in patients with alopecia areata is probably insufficient to justify routine screening 1.
Important Considerations
The management of alopecia areata should take into account the individual's psychological and social well-being, as well as their perceptions of body image and self-esteem 1.
From the Research
Laboratory Tests for Alopecia
The following laboratory tests are recommended for diagnosing alopecia:
- Complete blood count (CBC) 2
- Ferritin levels 3, 2
- Thyroid stimulating hormone (TSH) levels 3, 2
- Vitamin D 25OH levels 2
- Vitamin B12 levels 3
- Hemoglobin levels 3
- Hair pluck and scalp biopsy may also be required in some cases 4, 2
- Iron metabolism tests, such as serum iron and total iron-binding capacity, may be useful in some patients 5
- Hormone tests, such as sex hormone binding globulin (SHBG), total testosterone, and dihydroepiandrostendione (DHEAS), may be considered in patients with female pattern hair loss 5
Specific Tests for Different Types of Alopecia
- For telogen effluvium, ferritin, hemoglobin, and vitamin B12 levels may be significantly lower, and the number of patients with vitamin D, ferritin, hemoglobin, and vitamin B12 deficiencies may be significantly higher 3
- For androgenetic alopecia, hormone tests, such as sex hormone binding globulin (SHBG), total testosterone, and dihydroepiandrostendione (DHEAS), may be considered 5
- For alopecia areata, laboratory tests may not be as useful, but a complete blood count, ferritin, thyroid stimulating hormone, and vitamin D 25OH may still be ordered 2