Information about cause, treatment, and prevention

What Are Keloid Scars?

People with darker skin are more prone to forming 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.

How do keloid scars form?

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
Disclaimer: This website is not intended to replace professional consultation, diagnosis, or treatment by a licensed physician. If you require any medical related advice, contact your physician promptly. Information presented on this website is exclusively of a general reference nature. Do not disregard medical advice or delay treatment as a result of accessing information at this site. Just Answer is an external service not affiliated with
Some authorities believe that AKN is not a true keloidal condition but
rather a separate condition with hypertrophic scarring.
Dissecting cellulitis of the scalp.
A derivative of vitamin A; commonly known by one of its brand names,
Accutane™, which is no longer sold in the United States.
Argon lasers have a different wavelength than pulsed dye or CO2
lasers sometimes used to treat keloids.