What is the difference between acne and rosacea?

[Guide]

For a long time, as noted by the late late Dr. Albert Kligman, rosacea was referred to as 'Acne Rosacea', which he said, "It is interesting that the original term for rosacea was "acne rosacea”, which has more features in common with acne than currently realized. If the “acne” portion had been retained in the later works, rosacea might have received much greater investigative attention." [1] 

So what is the difference? Generally, rosacea is accompanied by flushing but not always and usually is the differentiating sign/symptom diagnosing rosacea.  Acne (Vulgaris) is generally found in young adults and teenagers. Rosacea usually presents itself in later adulthood. Rosacea usually does not present with blackheads or comedones and is generally restricted to the nose, cheeks, chin and forehead. Acne can present itself also on the neck, chest and back as well as the facial region. One of the key differences is that acne treatments, such as benzoyl peroxide or salicylic acid usually exacerbates rosacea. Rosacea in about half the cases involve the eyes accompanied by redness in the ocular regions. 

However, Acne Vulgaris can co-exist with rosacea. 

A proper diagnosis needs to be from a physician. [2]

"The two diseases can be differentiated based on characteristic profile of the immune cell infiltrates at the periphery of disease lesions." [3]

Etcetera

Diagnosing Acne vs. Rosacea (Stanford Medicine 25)

Rosacea Signs in Two Minutes

What Does Rosacea Look Like?

End Notes

[1] A Personal Critique on the State of Knowledge of Rosacea 
Albert M. Kligman, M.D., Ph.D.
publikation_kligman.pdf

[2] Diagnosing Rosacea

[3] PLoS One. 2021; 16(3): e0248650.
Elucidating the immune infiltration in acne and its comparison with rosacea by integrated bioinformatics analysis
Lu Yang, Yan-Hong Shou, Yong-Sheng Yang, Jin-Hua Xu