Is androgenetic alopecia a "diagnosis of exclusion" ?

Is AGA a diagnosis of exclusion ?

Some diagnoses in medicine are referred to as “diagnoses of exclusion.” What this means is that once every other possible diagnosis has been eliminated, one can finally make a certain diagnosis.

I’m often asked if androgenetic alopecia (AGA) is a diagnosis of exclusion. That answer is no.

AGA is not a Diagnosis of Exclusion

Androgenetic alopecia is a unique condition. It’s not just a diagnosis that gets made once everything else has been ruled out. It’s not a diagnosis that gets made after doctors say “Oh, we can’t think of anything else it could possible be - it must be AGA !”

That’s not how it works.

Androgentic alopecia is unique. It’s a hair condition that causes hairs to become thinner and thinner over time in certain areas of the scalp.

AGA in Males

In males, AGA typically starts in the temples of the crown. Some men experience hair loss in the front, middle and crown areas of the scalp even in the beginning stages. This is known as diffuse patterned alopecia or “DPA”). Some men experience thinning all over the scalp in a less common subtype of androgenetic alopecia called diffuse unpatterned alopecia or “DUPA.”

AGA in Females

For women with AGA, hair loss occurs in many different forms. AGA in females typically has a different pattern of hair loss than AGA in males. Hair loss may occur in the frontal scalp/temples or in the middle scalp and/or crown. Some women do experience a diffuse pattern of loss as well. In general diffuse types of hair loss are much more commonly seen in women than in men.

All forms of AGA, whether in males or females are associated with miniaturization of hair follicles - this follicles gets skinnier and skinner over time and this can be seen when the scalp is examined up close. A biopsy is usually not necessary but the biopsy will nicely capture this phenomenon of ‘miniaturization’ whereby the pathologist will report that the ratio of thick hairs to thin hairs is less than 4:1 (the so called terminal to vellus hair ratio).

Conclusion

AGA is not a “diagnosis of exclusion.” AGA is a diagnostic entity unto itself with clear clinical, dermatoscopic and histological features.