What stage of acne is characterized by the presence of cysts?

The presence of cysts is a hallmark of Stage 4 acne, which is often referred to as cystic acne. This stage is characterized by deep, painful, and inflamed lesions that can form large, fluid-filled cysts under the skin. Cystic acne represents a severe form of acne that can lead to significant scarring and requires advanced treatment options.

In earlier stages, such as Stage 1 through Stage 3, the lesions are typically less severe and can include comedones (blackheads and whiteheads) and inflammatory pimples, but do not exhibit the cystic formations found in Stage 4. Therefore, recognizing Stage 4 as the stage of acne where cysts are present is crucial for appropriate diagnosis and treatment.