Difference Between Keloid and Hypertrophic Scars (With Table)

Keloids and Hypertrophic scars are caused due to cutaneous injuries such as burns, insect bites, acne and other skin problems. Both the scars are results of the overproduction of collagen which is a main structural protein found in our skin. A keloid scar is known to spread beyond the boundaries of the original wound whereas a hypertrophic scar does not spread and grows within the boundaries of the wound. Let us understand the difference between these two wounds in more detail.

Keloid Scars vs Hypertrophic Scars

The main difference between a keloid and hypertrophic scar is that the keloid scars are larger scars and irregular in shape on the other hand hypertrophic scars are mild and elevated.

Keloid scars are smooth and dense outgrowths of fibrous tissue which may exceed the area of the original wound. These can form immediately after a wound or sometime later and are very uncomfortable and itchy. It can range from red to purple to brownish scar which is smooth and dense. A keloid scar can also be a permanent scar as it is the benign growth of the skin.

On the other hand, hypertrophic scars are mild as compared to the former. The scar is hyperemic, that is, excess of blood flow in a body part. It is elevated above the surface of the skin and can also become thick after some time. It can appear as a pinkish or dark reddish scar which is formed due to excess tension around the wound.

Comparison Table Between Keloid Scars and Hypertrophic Scars

Parameters of Comparison Keloid Scars Hypertrophic Scars
Appearance Red to brown and they cross the boundary of original wound Pink to red and they do not cross the boundary of the original wound 
Target sites Shoulder, chest, cheeks, earlobe, jaw Joints, elbows, arms 
Thickness  Abnormally thick  Normal thickness is visible and sometimes there is no thickness  
Structure  Irregularly pale Parallelly oriented to the epidermal surface   
Elevation  Sharp elevation seen, more than 4mm  Often elevated  

What Are Keloid Scars?

A keloid scar is huge in appearance as it spreads beyond the boundaries of the original wound. It can be identified by thickness and lumpiness which can appear anywhere on the body. These wounds are much larger than the original wound and commonly found areas are chest and shoulder regions. It does not appear on the face but can target the areas of the jawline and neck.

These are not harmful to one’s health but a person having a keloid scar may lead to cosmetic concerns. Sometimes these scars appear after an injury such as a simple cut or any other wound. If the damage appears to be normal then the repairing can happen through a process called regeneration of tissue. But in case of a serious injury then damaged tissues gets inflamed and appears larger in size. These can also be caused by getting a tattoo or piercing.

Causing discomfort and irritation is the main role of a keloid scar. These can form on a large surface of the body and become a hard and tight scar. More than a health concern, these are more of a cosmetic concern and a person can be conscious about appearance if the size of the scar is large.

What Are Hypertrophic Scars?

A hypertrophic scar is characterized by a thick appearance and develops only where the skin is injured. It does not cross the boundary line of the wound. This scar is a result of the overproduction of collagen and can happen as a result of someone’s skin type as well. These scars result from tension all around the wound having a thick red appearance which can last for a couple of years.

Hypertrophic scar arises due to an abnormal response to an injury. These are not very dangerous but lead to severe itching and redness. Both medical and home treatments are available to get rid of a hypertrophic scar.

The scar could be characterized by restrictions in the movement as the skin is no more flexible. Visible and elevated scars do not spread into the neighboring tissues and are caused due to excess deposition of fibroblast derives extracellular matrix proteins.

Main Differences Between Keloid Scars and Hypertrophic Scars

  1. Keloid scars appear on the earlobes, shoulder or chest region and cheeks whereas hypertrophic scars can develop anywhere on the body. 
  2. The color of a keloid scar is pink to purple and the hypertrophic scar is reddish-pink. 
  3. A keloid scar can grow beyond the boundaries of the original wound but hypertrophic scars remain within the boundaries of the original wound.  
  4. The keloid scars have high rate of recurrence whereas hypertrophic scar is easier to treat as compared to the former.
  5. Keloid scar is irregular in appearance whereas hypertrophic scar is often elevated.  

Conclusion

Both keloid and hypertrophic scars are formed in almost a very similar way but there are slight differences between the two. Scars are type of skin lesions which are not always too harmful for a person but can make a person concerned about their appearance. A keloid scar is a type of scar which crosses the boundaries of the original wound and forms a huge shape. On the other hand, hypertrophic scar does not cross the original wound’s boundary. This is the main difference between the two types of the scars.

Keloid and hypertrophic scars are the type of scars which arise due to chronic inflammation in the reticular dermis skin layer. The reason of their appearance could be physical trauma or any kind of irritation on the skin surface.

Many treatments are available for these scars which includes both home remedies and medical treatments. Other type of treatments are, cryotherapy, occlusive dressing, radiation therapy, compression therapy etc. It is always advised to consult a doctor to get rid of these scars.

References

  1. https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1524-4725.1999.98257.x
  2. https://www.sciencedirect.com/science/article/pii/0738081X94902542

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