Definition and Overview

A hypertrophic scar is a skin condition that causes a raised scar to form on the skin. The scar forms due to excessive amounts of collagen. Scars commonly form after a skin injury. They tend to fade and disappear within a short period. But if the body has an abnormal response to the injury, it may cause the scar to become thicker than normal. When this happens, a hypertrophic scar forms.

These scars are similar to keloids in many ways. Like keloids, they also often form in areas of the skin that were previously injured. They are very common in areas affected by pimples, cuts, burns, or piercings. They are more likely to form if the injury also affected the deeper layers of the skin (dermis).

However, they do not grow as big as keloids. They are also more common and are more responsive to topical treatment than keloids.

Causes of Condition

Not all wounds cause hypertrophic scars to form. Normally, the body reproduces new cells to repair the damage caused by the wound. It produces new collagen fibers to replace the old collagen that has broken down due to the injury. But sometimes, the body produces too much collagen, causing the skin to grow and thicken.

The body’s tendency to produce certain amounts of collagen depends on each person’s skin type and unique healing tendencies.

There are certain factors that can make a person more likely to suffer from hypertrophic scars. These include:

  • Ehlers-Danlos syndrome - This is an inherited disorder that affects the connective tissues of the skin. One of its symptoms is abnormal scar formation. Patients who suffer from this condition are more likely to form hypertrophic scars after suffering from a skin injury.

  • Mechanical tension or motion in the wound area - Wounds located over or near joints tend to experience more tension or motion due to the patient’s movements. Such wounds are more likely to produce hypertrophic scars.

  • Wound infection - If a person’s wound becomes infected, he or she has a higher risk of hypertrophic scar formation.

  • Severe inflammation - Wounds that become severely inflamed may cause the skin cells to produce more collagen during the healing process.

  • Big wounds that are left to heal without stitches - Some wounds, especially big or deep ones, need to be stitched for proper healing. If such wounds are left to heal without stitches, they may heal abnormally. This makes hypertrophic scars more likely to form.

Key Symptoms

A hypertrophic scar is a raised scar that forms on the surface of the skin, usually on top of a previous skin injury.

These scars receive blood supply from nerves and blood vessels. This is what causes them to keep growing. Thus, the scars can thicken continuously for a long time, usually within six to twelve months. They tend to become red and thick in appearance. They can also become itchy and painful. However, they do not extend beyond the injured area.

The scars can improve in appearance and symptoms may subside over a period of one to two years even without treatment. On the other hand, they can also become worse. The itching and pain can become more intense. Also, if the scar is located near a joint, it can also restrict movement.

However, in most cases, hypertrophic scars cause only mild discomfort. They are not dangerous or life-threatening in any way. Most patients who seek treatment for such scars only do so for cosmetic reasons.

Who to See and Types of Treatments Available

Patients with red, raised, and thick scars forming over an injured part of their skin may consult a dermatologist for treatment and advice. Dermatologists are doctors who specialise in the treatment of skin disorders.

However, if the hypertrophic scar is new or is less than a year, doctors will not treat them yet. This is because it usually takes scars six months to one year to mature. During this period, the skin and the scar itself are continuously changing. The body may also be in the process of repairing the scar by itself. This is why it is best to wait up to a year before seeking treatment for a hypertrophic scar.

Patients who wish to have a mature hypertrophic scar treated have a number of options. The first line of treatment includes creams and silicone pads. These can be bought over the counter. They are simply applied over the raised scars. Thus, they are safe and easy to use. They are helpful in relieving symptoms, including pain, swelling, and itching. However, they may take up to three months to work. The silicone pads have to be worn regularly for 12-24 hours per day. Topical creams, on the other hand, have to be applied several times a day in order to be effective.

Massaging or applying pressure over the scars is also beneficial. Doing so can weaken the scar tissue. This can help reduce the size of the scar.

Various scar therapies are also available for those who wish to have their scars treated. These include:

  • Corticosteroid injections - With this treatment, steroids are injected into the scar. This can soften and flatten the scar. The injections are administered once every six weeks. However, there is a limit to the number of injections a patient can receive. This is because steroid injections can also weaken normal skin tissue around the scar.

  • Laser therapy - Applying laser energy to the scar can help lighten and flatten it.

  • Cryotherapy - The scar is frozen and flattened using liquid nitrogen. This is one of the safest and most effective treatments for hypertrophic scarring.

  • Bleomycin - This is a metabolite of soil bacteria. It can be injected directly into a hypertrophic scar. So far, ongoing studies show promising results. It can improve the scar’s appearance as well as relieve pain and itching.

Lastly, patients may also consider surgery. During surgery, the scar is cut from the surface of the skin. The area is then repaired with stitches. Surgery aims to make the affected area heal itself. It also helps eliminate negative factors. These include infection, inflammation, or mechanical tension. This encourages the wound to heal normally.

Surgery is always the last option. This is because it is invasive. It is only considered for patients whose scars are severe or are causing serious symptoms. This is true for scars that restrict movement, cause intense pain, or do not respond to other non-surgical treatments.


  • Kokoska MS. (2016). Hypertrophic Scarring and Keloids.

  • Rabello FB, et al. Update on hypertrophic scar treatment. Clinics (Sao Paulo). 2014 Aug; 69(8): 565–573.

  • Juckett G, et al. (2009). Management of keloids and hypertrophic scars.

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