Investigations
1st investigations to order
hair-pull test
Test
Used to measure the telogen hair density. [Figure caption and citation for the preceding image starts]: Hair-pull testFrom the collection of Paradi Mirmirani MD; used with permission [Citation ends].Approximately 50 to 100 hairs are grasped between the thumb and the middle and index fingers and then firmly pulled.
The test should be performed on the frontal and occipital area for comparison.
Result
Negative (≤3 hairs pulled)
thyroid function test
serum ferritin
Test
Important to exclude iron deficiency in both men and women.
Result
normal levels
Investigations to consider
FBC with differential
Test
Excludes anaemia and infection as cause of hair loss.
Result
normal
comprehensive metabolic panel
Test
Excludes hepatic disease as cause of hair loss.
Result
normal
antinuclear antibodies
Test
Evaluates for autoimmune disease as cause of hair loss.
Result
normal
rapid plasma reagin
Test
Excludes syphilis as a cause of hair loss.
Result
negative
free testosterone
Test
Required if signs of hirsutism on other parts of body, irregular menstruation, and/or severe acne are present, to rule out Cushing's disease, adrenal hyperplasia, ovarian tumour, or polycystic ovary syndrome (PCOS).
Result
normal to increased in women with hyperandrogenism
serum dehydroepiandrosterone (DHEA)-sulfate
Test
Required if signs of hirsutism on other parts of body, irregular menstruation, and/or severe acne are present, to rule out adrenal source of excess androgens.
Result
normal to increased in women with hyperandrogenism
sex hormone-binding globulin
Test
Required if signs of hirsutism on other parts of body, irregular menstruation, and/or severe acne.
Result
normal to reduced in women with hyperandrogenism
dermatoscopy/trichoscopy
Test
Usually not necessary but may be used as a diagnostic tool to distinguish from other non-scarring forms of alopecia.
Result
miniaturised hair follicles and follicular ostia
scalp biopsy
Test
Usually not necessary but may be used as a diagnostic tool to distinguish from other non-scarring forms of alopecia.
Result
increased vellus hairs and miniaturised hair follicles; increased telogen hairs
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