Alopecia Diagnosis
History
Androgenic alopecia in men/women
- Some do not have a family history
- An androgen-dependent trait
- Family history of alopecia
- Patients often give a history of emotional trauma/stress prior to its onset
- Usually rapid hair loss in a well-defined, typically round area
- Patients complain of 1-4 cm2 of hair loss on the scalp
- Patch is usually clean-looking without scaling
- May be asymptomatic, but some patients experience paresthesias with pruritus, burning sensation, pain or tenderness prior to loss of hair
Laboratory Tests
Androgenic alopecia in males/females
- Rarely indicated for MPHL and females with normal menstrual cycle
- Include pull test and examination of facial and body hair and nails
- Pull test must be performed in the right and left parietal areas, frontal and occipital areas and in visibly affected areas
- Hair pull test is positive in active early hair loss but negative in long standing hair loss
- Pull test must be performed in the right and left parietal areas, frontal and occipital areas and in visibly affected areas
- If with evidence of androgen excess in FPHL, consider total testosterone, free testosterone, dehydroepiandrosterone sulfate (DHEAS), prolactin levels
- If without evidence of androgen excess: Rule out thyroid disease, syphilis, iron deficiency and systematic lupus erythematosus (SLE) as cause of hair loss
- Biopsy is sometimes necessary for FPHL to exclude chronic telogen effluvium, diffuse alopecia areata or cicatricial hair loss
- Trichoscopy (also known as dermoscopy) should be considered in doubtful cases
- Features typical for androgenic alopecia include vellus hairs >10%, increased percentage of follicular units with only 1 hair shaft, hair shaft thickness heterogeneity of ≥20%, yellow dots, perifollicular discoloration, empty follicles, circle hair and honey comb pigment pattern
Alopecia areata
- Diagnosis is usually clinical
- Hair pull test may be positive at the margins which is indicative of active disease
- Trichoscopy (dermoscopy) may be helpful for visualizing findings consistent with alopecia areata
- Features typical of alopecia areata include short vellus hairs, black dots, yellow dots, tapering hairs and broken hairs
- Patch biopsy of the scalp in rare difficult cases
- Thyroid stimulating hormone (TSH) level determination is routinely performed by many physicians to rule out any related thyroid abnormality