From the Guidelines
In the setting of acute hair loss, initial testing should include a complete blood count (CBC), thyroid function tests (TSH, free T4), and a comprehensive metabolic panel, as these tests help identify common causes like thyroid disorders and nutritional deficiencies. Additional testing may include antinuclear antibody (ANA) testing for autoimmune conditions, vitamin D levels, and hormone panels (testosterone, DHEAS) particularly in women with signs of androgen excess 1.
Key Considerations
- A detailed medical history is essential, focusing on recent illnesses, medications, stressors, and family history of hair disorders.
- Specific testing should be guided by the clinical presentation - for example, fungal cultures for suspected tinea capitis or a pull test to assess active shedding.
- Iron studies (serum iron, ferritin, total iron binding capacity) may not be necessary as the evidence for an association between iron deficiency and alopecia areata is not strong, with some studies finding no differences in iron status between patients with alopecia areata and controls 1.
- A scalp biopsy may be necessary if the diagnosis remains unclear after initial testing.
Diagnostic Approach
- The diagnosis of alopecia areata is usually straightforward, but can be confused with other conditions such as trichotillomania, tinea capitis, and telogen effluvium 1.
- Dermoscopy can aid in the diagnosis of alopecia areata, highlighting features such as dystrophic hairs with fractured tips (exclamation mark hairs) and hairs fractured before emergence from the scalp (cadaverized hairs) 1.
- The clinical presentation and medical history should guide the diagnostic approach, with a focus on identifying underlying conditions that may be contributing to the hair loss.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Testing for Acute Hair Loss
In the setting of acute hair loss, several tests can be performed to determine the underlying cause.
- A comprehensive history and physical examination are essential in evaluating hair loss, as they can help identify potential causes such as malnutrition, autoimmune diseases, and endocrine disorders 2.
- Targeted laboratory testing may include:
- Complete blood count
- Ferritin
- Thyroid stimulating hormone (TSH)
- Vitamin D 25OH 3
- Scalp biopsy can confirm a diagnosis, especially in cases of cicatricial alopecia 3.
- Hair pull, hair tug, Hair Card, and hair mount can aid in evaluating the hair and scalp 3.
- Thyroid profile testing may be relevant in certain types of alopecia, such as alopecia areata, which has been associated with thyroid dysfunction 4, 5.
Specific Tests for Different Types of Alopecia
- For alopecia areata, testing for thyroid dysfunction, such as TSH and antithyroid antibodies, may be considered, especially if the patient has a personal or family history of autoimmunity 4, 5.
- For telogen effluvium, thyroid hormone assays may be performed to rule out underlying thyroid anomalies 5.
- For frontal fibrosing alopecia, thyroid testing may be considered due to the higher prevalence of thyroid conditions in this population 5.