What Are Keloid Scars?
Keloids are abnormal scar tissue that develops as a skin wound caused by surgery, trauma, certain skin conditions, and in some minor cases spontaneously due to unknown or forgotten small injury months or years later.1 The term was coined from the Greek word chele for crab claw in describing how some keloids have claw-like, irregular borders that extend over the skin and beyond the original wound area. Chickenpox, ear piercing, vaccines, and acne are common situations where keloids form.2-3
Although keloids are benign, the associated cosmetic and pain considerations make it a subject of intensive research. Treatment options include surgical excision, cryotherapy, laser and light therapies, radiation, compression, and medications. Medications are typically administered by injection directly into the keloid (e.g., corticosteroids) or topically in an ointment (e.g., retinoic acid). Off-label application of some chemotherapy drugs (e.g., doxorubicin and tamoxifen) and immunotherapy creams (e.g., imiquimod and tacrolimus) suggest they may effectively prevent and treat keloids after surgery, but they are not currently approved for scar or keloid use by the U.S. Food and Drug Administration (FDA).3
The increased overall understanding of the pathophysiology of scar and keloid formation has improved and expanded treatment options, and different treatments can be combined to improve results. However, most treatments do not produce permanent results and the growths tend to re-appear. This makes prevention all the more important. Understanding the risk factors and what precautions can be taken to minimize these factors can help prevent or limit the extent of the scar tissue.3-4
Researchers have uncovered powerful phytochemicals in natural herbs and botanicals that may play an important role in keloid prevention and treatment. This isn’t so surprising once you realize that the well-known skin care ingredient retinoic acid is also an all-natural compound derived from vitamin A. Preliminary studies and even some clinical trials support further investigation into the natural medicinal benefits of gotu kola, onion extract, quercetin, soy, green tea, and vitamin D.
In general, a keloid is an abnormal connective tissue response to a wound or inflammation due to surgery, burns, or some other traumatic skin condition that causes a sore (e.g., acne or chickenpox). Cosmetic appearances, itchiness, pain, and pressure are primary concerns for people with keloids.1,3
Different than other scar tissue, keloids are benign tumors that usually extend to adjacent tissues beyond the wound region.2 They can feel soft or rubbery and hard, and when they first form tend to be red but fade over time.3 Keloids often do not have hair follicles or secretory glands.3 Although it is sometimes difficult to determine whether a scar is a keloid or not in the early stages, there are other visible and microscopic differences between keloids and hypertrophic scars as well:1,5
Dermatologists often categorize keloids into different types by where they appear on the body, causes, and treatment methods. Some of these are:
| Type | Cause or Prevalence | Location & Description |
|---|---|---|
| Post-incisional keloids | Following surgery, most common in Caucasian population.2 |
Typically in areas that are frequently stretched or flexed (e.g., chest, shoulder, back) with the exception of palms and soles.2 |
| Ear lobe keloids | Mostly as a result of ear piercing but also other trauma; greater risk of occurrence in children under age 11.2,7 |
Shiny and smooth, these scars can take a number of globular shapes in different areas of the ear lobe and other parts of the outer ear.2 However, they are more common on the back of the lobe.7 |
| Spontaneous keloids | Unidentified past trauma or inflammation; occasionally linked to malignancy.2 |
Thickened, dense, fibrous raised nodules on the skin surface anywhere on the body.8 |
| Acne keloidalis nuchae (AKN) | Chronic irritation and inflammation of hair follicles usually related to friction from close shaving, collars, or helmets and minor infection; typically in African-American males or others over age; scarring of ingrown hairs typically 50.2,8 |
Scalp and nape of neck; individual raised round bumps may join together to form keloid/keloid-like nodules.2 |
| Perifolliculitis capitis | Almost always occurs in adult men (ages 18-40) and more commonly in African-Americans; chronic inflammation of the hair follicles.8 |
Firm and painful nodules on the scalp that often join together in ridges; accompanying hair loss and discharge of pus.8 |
| Sessile keloids | Any skin trauma.2 | These flattened, thick lesions can occur anywhere on the body.2 |
| Acne | Usually occurs as deep inflammatory acne lesions heal, but can develop with less severe lesions in people prone to keloids.10 Acne patients treated with isotretinoin along with argon laser or dermabrasion.11 |
Anywhere on the face and body that acne occurs.10 |
rather a separate condition with hypertrophic scarring.
Accutane™, which is no longer sold in the United States.
lasers sometimes used to treat keloids.