Workup of pattern hair loss in men and women

Age of onset, time course, severity, hair loss distribution, progression (periods of shedding), accompanying symptoms
Medical history
Gynecologic history
Medication and supplement list
Family history of hair loss, androgen excess, and metabolic disease
Physical examination
Distribution of hair loss
Hair caliber and texture
Clinical features of scalp
Nail changes
Hair-pull test
Scalp biopsy
Laboratory testing
Complete blood cell count
Comprehensive metabolic panel
Antithyroid antibody testing
Thyroid-stimulating hormone with or without free thyroxine
Iron evaluation (serum ferritin, serum iron, total iron-binding capacity)
Free and/or total testosterone
Dehydroepiandrosterone sulfate
Serum prolactin
Hydroxy-25 vitamin D