Depending on the way the scars are formed, they can be grossly divided in three categories:
1. Average healing level with the surrounding skin leads to normal scar
2. Under healing leads to weak, atrophic, depressed and stretched scars
3. Over healing leads to slightly raised hypertrophic scars
4. Continued over healing leads to large, raised and growing or spreading keloidal scars
In grossly inflamed acne (nodulo-cystic or pustular) if the underlying collagen structure within the dermis gets disrupted it gets reflected as a depressed (sunken) part on the surface of the skin after healing. Some acne scars are small in diameter but deep, while others are wide and shallow. These are atrophic types of scars. Atrophic scars, though they are caused by an inflammatory reaction, ironically, they are also treated by deliberately inducing a controlled dermal inflammation. Inflammation increases blood flow within the dermis which promotes the release of Fibroblast Growth Factor (FGF). FGF is a potent stimulator of new cell growth from both axis (horizontal and vertical). Over time when the procedures are repeated the new collagen growth reduces the depth of the scars gradually.
ICE PICK SCARS
Common after acne which have been forcefully squeezed, pinched or extracted by nailing. Ice pick scars are deep-pitted scars that make the skin look like it had been jabbed with an ice-pick. These are best treated by Fractional CO2 laser resurfacing.
Common after acne. Most often multiple saucer like scars coalesce together to form an irregularly shaped patch of scars. These are best treated with subcision, followed by Fractional CO2 laser. Depressed scar area can also be filled with Dermal Filler.
Combination of depressed and rolled scars, coalescing together and causing obvious disfigurement. Most often these type of scars are genetically influenced. Steroids are used to weaken the scar, followed by smoothening the skin with Fractional CO2 laser.
Hypertrophic or keloid scars occur due to the same triggering factors (inflammatory reaction). However, in hypertrophic scars, the disrupted collagen network is replaced by an overgrowth of dense fibrotic tissue; giving it the elevated, brownish, thick cord like appearance.
Though a rare type after acne, hypertrophic scars are more obvious and difficult to conceal. These patients have a tendency for keloid and have to be treated cautiously. Corticosteroid injections are used to flatten the scar, followed by smoothening the skin with IPL or Fractional CO2 laser.
POST TRAUMATIC SCARS
These scars occur following trauma, in majority cases; road accidents. They appear as a combination of
fine thickened lines, flat or raised areas of varying sizes, which may or may not be discolored.
TRAUMATIC TATTOO SCARS
Sometimes they have traumatic tattooing due to tar particles getting embedded. In addition to revision surgery, corticosteroid injections are used to flatten them, Q switched laser to remove pigment followed by smoothening the skin with IPL or Fractional CO2 laser.
POST SURGICAL SCARS
These scars are the result of surgery. At their best, they appear as a fine, flat (hair line scar) or slightly thickened lines which may or may not be discolored. At their average, they have some unacceptable width, and dotted needle marks along both sides called cross hatches or multiple short transverse scars crossing the main scar line due to tight tying of sutures called rope ladder pattern. At their worst, they can be depressed, stretched, hypertrophic and even keloidal.
Surgical scars which result out of either suturing under tension or poor dermal apposition may lead to spread scars. Typically they are spindle shaped, widest at middle and depressed. They are covered with thin and atrophic epidermis.
STRETCH MARKS (STRIAE DISTENSIS)
This is similar to spread scar but here there is no scar on the surface to begin with. Instead, the dermal collagen gives way due to rapid stretching of the skin as commonly seen on abdomen during later pregnancy or in teenagers on shoulders, arms, breasts and thighs during rapid growth and weight gain.
Any of the above type of scars can be dark in color i.e. hyper pigmented, at least initially. Though the dark color improves over time, it may not and require treatment with de-pigmenting creams and/or lPL or Lasers.