Based on how the collagen level is disrupted with the healing of acne, there are broadly two types of acne scars:
- Atrophic/Depressed Acne Scars- This form is due to a lack of collagen. Subtypes include ice-pick scars (narrow and deep indentations), boxcar scars (broad indentations with sharp edges), and rolling scars (uneven indentations with wave-like edges).
- Raised Acne Scars - This form is due to excess collagen. Subtypes include hypertrophic scars (scar tissue confined within the original acne wound) and keloid scars (scar tissue grown beyond the original acne wound).