The first type of acne scar, known as hypertophic or keloid, is where too much collagen is produced, stretching the skin. The second category is where there has been a loss of tissue, similar to the damage caused by chicken pox. Ice pick scars fall into this second category.
These scars are usually formed as a result of acne leading to a papule. This is a type of skin lesion which is particularly narrow on the surface. However, the resulting scar will usually run deep into the skin. Because of this shape, and the way the scar usually has a jagged edge, it can be best envisioned by imagining the damage left by being stabbed with an ice pick. It is one of the most visibly striking types of acne scar.
Because ice pick scars are so deep, they usually extend to the dermis or subcutaneous skin layers: the second and third layers from the surface respectively. This means the scars cannot be treated by some of the more common acne scar methods such as dermabrasion which aim to smooth out the top layer of skin. The scars are also usually too deep for punch grafts, in which skin from elsewhere in the body is implanted into the gaps created by the scar.
In some cases, the effects of ice pick scars can be lessened without having to remove the scar tissue. This can be done by stretching out the skin, which smoothes out the visible damage. However, this only works with softer scars.
One method of treating ice pick scars is laser treatment. This can involve using a laser to wound the affected area, which encourages the body to regenerate the skin, which softens and reshaped the scarred area. In other cases, the laser is actually used to remove the scarring completely.
Another method is punch excision treatment. This involves using a tool to remove a section of skin in the affected area under local anesthetic. The surrounding skin is them stretched across and stitched into place until it heals over. This method is not always as smooth or efficient as laser treatment, but is considerably cheaper.