Investigations

1st investigations to order

hair-pull test

Test
Result
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].com.bmj.content.model.Caption@7e61b79cApproximately 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

Test
Result
Test

Important to exclude thyroid dysfunction in men and women with diffuse hair loss.[9][27]

Result

normal

serum ferritin

Test
Result
Test

Important to exclude iron deficiency in both men and women.

Result

normal levels

Investigations to consider

FBC with differential

Test
Result
Test

Excludes anaemia and infection as cause of hair loss.

Result

normal

comprehensive metabolic panel

Test
Result
Test

Excludes hepatic disease as cause of hair loss.

Result

normal

antinuclear antibodies

Test
Result
Test

Evaluates for autoimmune disease as cause of hair loss.

Result

normal

rapid plasma reagin

Test
Result
Test

Excludes syphilis as a cause of hair loss.

Result

negative

free testosterone

Test
Result
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
Result
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
Result
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
Result
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
Result
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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