Keloid: know the basics.

Genetics: what is keloid tendency? Is keloid genetic disease ?

Keloid has very much diverse and varied presentations. It may present as a single or multiple, discrete or confluent , thin linear lesions or large giant nodular patches. This variety of presentations hints at complex and multi-gene inheritance. Those having a mutation (change) in a single gene may have single or less severe keloid while those with multiple faulty genes may show more aggressive pattern of keloids. Specific genes are reported in Chinese and Taiwan population but larger studies are required to know which genes are at fault in each population. Such studies in India are missing and skincity is planning to take up one genetic study on Indian pattern of inheritance.

Genetically predisposed individuals develop Keloids after injury to the skin that acts as a trigger. This triggering injury could be anything from minor inflammatory skin condition, acne, chicken pox, vaccination; to body piercing, surgical wounds, burns, etc. Though not all keloid prone individuals or all those with family history will develop keloid, while in the same keloid patient, not all injuries will evolve into keloids.

How many members in family have developed keloid is another predictive factor for severity of keloid. How many siblings, father, mother or both? How many generations?

Race and ethnic distribution

Dark-skinned individuals of African, Asian, and Hispanic descent have higher rates of keloid development compared to Caucasians. The incidence in these darker-pigmented populations ranges from 4.5% to 16%. The incidence is notably higher during pregnancy and puberty. A positive family history increases the risk for the development of keloids although no specific gene has been identified. The chance of getting keloid, its severity and chance of it running in family increases with skin colour. Incidence of keloid is zero in albinos while least in white skinned Caucasians while moderate in brown coloured Indian and worst in dark coloured Africans. This clearly signifies the importance of melanin or skin colour.

In India also there is wide variation in skin shade across north to south of the country. It would be interesting to compare epidemiology of various ethnic groups in India. SkinCity has initiated such a research on epidemiology.

Pathophysiology: what's going wrong in keloid formation?

Keloids are a result of aberrant wound healing process. What is going wrong in wound healing here? Standard wound healing consists of three phases: (1) inflammatory (swelling), (2) fibroblastic (collagen formation), and (3) maturation (collagen remodelling) . In keloids, the fibroblastic phase continues, unchecked. Keloidal fibroblasts work harder, persist for longer, and have lower rates of apoptosis (don’t die early!) compared to ‘normal’ wound healing resulting in an overproduction of collagen. Collagen synthesis in keloids is 20 times greater than that of healthy skin and three times greater than a hypertrophic scar.

Keloid Pathology

The diagnosis of keloid is mainly clinical and no biopsy is required. If biopsy is taken and keloid tissue is observed under microscope, what is seen is increased whorls of thickened, hyalinized collagen bundles widely known as keloidal collagen. That is keloid collagen where collagen is haphazardly arranged like a stone while in hypertrophic scar though thick layer of collagen are seen but it is arranged parallel to skin and still organised enough to show vertical blood vassals. These vertical capillaries are collapsed in keloids.

Keloid: a disease of darker skin type

Keloid is basically a disease of skin of color. Very few in Caucasians are affected by keloids, while most severely affected community is African Americans. In between lies a variety of skin shade called Asian skin. Asian skin is again classified as yellow in far Asian like china and japan while brown in Indian subcontinent. Even in India a variety of ethnic subgroups show wide variations of skin color from light brown north Indians to dark brown south Indians. The prevalence of keloid in darker population ranges from 6 to 15% it would be interesting to observe differences between these subgroups.

Though number of people suffering from keloid may be more than ten crores, As this is a disease of dark skin and poor world, it has not attracted the attention or funding of scientific community. So indigenous research by local stake holders will be very much valuable. SkinCity has launched various research projects for keloids.

Trigger factors: what makes keloid worse?

Ok. Keloid occurs in genetically predisposed individuals and when a deep non healing or slowly healing wound occurs. But why only at certain age? Why only at certain places? Why some keloids on some body parts grow larger than other body parts? It is highly unpredictable though some patterns are observed.

What injury? previous skin trauma or inflammation. Lesions may develop as early as 1 to 3 months or as late as one year after injury. Spontaneous lesions are reported. Those may be due to very minor injury was not recalled or keloid might have developedafter months or even years of injury.

what are aggrevating factors

Role of appeandages in keloid growth.

Now remember two factors. Keloid has tendency to spread beyond boundary of original injury. Second any smaller inflammation will trigger second phase of wound healing ie fibroblast activation (collagen production) that doesn’t stop at all, once started. Skin has appendages like hair follicles, sebaceous glands (oil glands), sweat glands etc. To start with, a little encroachment of keloid on surrounding skin will block few appendages. These blocked hair follicles will act as source of irritation below keloid. Blocked oil glands will either form pimples (acne) or infection (folliculitis). So each appendage will act as a trigger of inflammation. It is observed that chest keloid is more common in hairy chest or acne prone skin.

Chest keloid starts with acne or hair follicle infection. In later age diabetes or low immunity will trigger infection and hence growth of keloid. In darker individuals hair are thicker and oil glands are more active (skin is more oily). Curly hair in darker individuals make them prone for pseudofolliculitis and hence for infection and inflammation. In skincity protocols meticulous attention is given in skin appendage management.

Traction and tension?

Shoulder or chest keloid will show growth in specific directions. This indicates body’s natural tension lines. Keloid becomes worse along lines of tension. In female the weight of the breast will determine line of tension. It is interesting that upper eyelid will never have keloid as skin there is always loose even when eyes open or closed.

Acne or pimple

Acne or pimple: it is very common trigger on chest and back. Especially if not treated, each acne become a slowly healing or non healing wound. It is interesting to know that steroids used in injection treatment of keloids can induce new acne formation.

Surgery

Surgery makes keloid worse

keloid is started in response to a small injury. Now treating that with another fresh set of injury is completely illogical. After surgery the recurrence rate (chance of keloid coming back) is almost 100%. So surgery is NOT the treatment of keloid. On the contrary it is most common cause of spread of keloid.

Steroid creams and steroid injections

Keloid creams and steroid injections

steroid, either cream or injections, will make the oil glands and hair follicles prone for infection or pimple formation, not only inside the keloid but also away from the lesion. So there should be a big NO to the steroids. In an yet unpublished study of skincity, Dr Dhepe observed that most of cases progressed from a small innocent keloid to big aggressive one are either due to surgery or steroid injections. Many doctors don’t know the correct way using steroid and end up causing new acne or hair follicle infection in patient thus inducing new keloids.