Decreased Hair in the Frontal Region
In this 49-year-old man with a one-year history of progressive hair loss and a positive family history, the most likely physical exam finding is decreased hair in the frontal region, consistent with androgenetic alopecia (male pattern baldness).
Clinical Presentation of Androgenetic Alopecia in Men
Male androgenetic alopecia follows a characteristic pattern of hair loss that primarily affects the frontotemporal, parietal, and vertex regions of the scalp, while notably sparing the occipital area. 1, 2
Expected Physical Exam Findings:
- Frontal hairline recession is a hallmark feature, with gradual thinning and eventual loss of hair along the frontotemporal regions 1, 2
- Parietal region involvement occurs as the condition progresses, with thinning extending across the crown 1
- Vertex (crown) thinning develops in conjunction with frontal recession 2
- Occipital region preservation is characteristic—hair in the temporal and occipital regions remains intact even in advanced cases 1
Key Distinguishing Features:
The pattern of hair loss in men differs significantly from women with androgenetic alopecia. Women typically exhibit diffuse hair thinning with pronounced involvement of the parietal region while maintaining their frontal hairline, whereas men develop the classic receding frontal hairline pattern. 1, 3
Why Other Options Are Less Likely:
- Decreased hair in the occipital region would be atypical for androgenetic alopecia, as this area is characteristically spared even in advanced male pattern baldness 1
- Thinning of eyebrows and facial hair are not features of androgenetic alopecia, which specifically affects scalp hair follicles in a defined pattern 4
Pathophysiology Supporting This Pattern:
Under androgenic influence, terminal hair follicles in genetically susceptible scalp regions undergo miniaturization, transforming into thin vellus-like follicles with shortened anagen phases. 1, 5 This process affects the frontotemporal and vertex regions preferentially due to differential androgen receptor sensitivity in these areas.
Clinical Pitfall to Avoid:
While lisinopril is mentioned in this patient's history, ACE inhibitors are not typically associated with androgenetic alopecia patterns. The British Association of Dermatologists notes that drug-induced anagen effluvium can mimic diffuse alopecia areata, but this would not present with the characteristic frontotemporal pattern seen in androgenetic alopecia 4