Short answer: It is mentioned in some of the oldest medical texts we have, insofar as any modern medical diagnosis can be gleaned from the nosology of a pre-modern people. For example, both Aristotle and the Hippocrates use the Greek word ionthoi to describe a pustular skin condition associated with puberty.

​

(for a full discussion, see:

​

Mahmood, N. F., & Shipman, A. R. (2017). The age-old problem of acne. International Journal of Women’s Dermatology, 3(2), 71–76. doi:10.1016/j.ijwd.2016.11.002)

​

Long answer:

​

The modern description of acne vulgaris dates to 1840, which using pathological anatomy essentially described a disorder of the pilosebaceous glands that has a variety of surface skin findings. Vulgaris means common, and it was described as being very common in young adults. Consider the amount of medical knowledge that we needed to even begin to think about this description. Microscopes would need to be invented (roughly 18th century for capable tools, if you consider when Leuwenhoek made his discoveries) for one thing. But you also need massive epistemic shifts in how doctors would view and classify disease. But doctors prior to the 18th century also viewed disease in the setting of balance of fundamental body fluids (the four humors). What we call "acne vulgaris" would be lumped in with a variety of other skin conditions, caused by environmental, dietary changes, and importantly sexual factors (Riolanus associated with menstruation, and Johnston with "fruitful venery"). In the 18th century, you then have the beginnings of nosology, with an attempt to classify diseases like a botanist -- looking at symptoms, and how they compare to other presentations. So for example, what we would call acne vulgaris was considered under a huge subset of the "species" "herpes". Plenck, a followed of Cullen intereseted in dermatology, for example, described would have roughly counted what we call acne vulgaris as part of the Class of Papulae, the Genus of Herpes seu Serpigo, and the Species of miliaris. It's not until the turn of the 19th century when a new idea of nosology -- that of pathological anatomy (or that disease comes from the tissues) comes around; first Morgagni described the sebaceous glands (mid 18th C). As doctors started to reclassify diseases on their pathological findings, acne vulgaris was rapidly described (see, for example, this illustration from 1838, showing the sebaceous glands and characteristic changes of different diseases, including acne vulgaris: https://commons.wikimedia.org/wiki/File:A_practical_treatise_on_the_diseases_of_the_skin_(electronic_resource)-_arranged_with_a_view_to_their_constitutional_causes_and_local_characters_(1838)_(14783479905).jpg?uselang=en-gb).

​

So, getting to the TL;DR -- "acne vulgaris" is not mentioned in older medical texts, because the modern definition of acne is contingent on a type of medical knowledge that localizes disease to different tissues (pathological anatomy). However, doctors have been describing what sounds like acne going back pretty much to the oldest medical texts.