A keloid is a type of raised scar that occurs when too much collagen builds up at the site of a healed skin injury. Keloids can form anywhere on the body, but are most common on the ears, shoulders, chest, back and abdomen. Keloids have a distinct appearance that helps set them apart from other types of scars.
Size and Shape
Keloids vary in size and shape. They are often larger than the original wound and can spread beyond the boundaries of the injury into surrounding normal skin. Keloids tend to have an irregular shape with lobules or bulbous projections emerging from a flat, smooth base. The texture is firm, rubbery and elevated above the surrounding skin.
Small Keloids
Smaller keloids may be round, oval or filamentous. Round and oval keloids are circumscribed lesions with a diameter less than 1 centimeter. Filamentous keloids have a linear shape and can extend along the site of a surgical incision.
Large Keloids
Larger keloids have a more lobulated, complex shape. Giant keloids with a diameter greater than 5 centimeters can cover extensive areas with sizable exophytic masses. These severe cases cause significant functional impairment and cosmetic concerns.
Color
The color of a keloid depends on its age:
- Newly formed keloids (less than 1 year old) are pink to red in color.
- Mature keloids (greater than 1 year old) are pale white to flesh-colored.
- Keloids in darker-skinned individuals may be hyperpigmented and darker than the surrounding normal skin.
Surface Texture
Keloids have a shiny, smooth surface texture. The surface is often tense and may resemble a stretched, inflated balloon. Telangiectasias or dilated blood vessels are sometimes visible on the surface, creating a variegated red to blue appearance.
Firmness
Keloids feel extremely firm and rubbery. They are less compressible than surrounding normal skin due to the excessive collagen deposition. Gentle pressure on a keloid causes blanching as blood is displaced, followed by quick return to the baseline color once pressure is released.
Location
Keloids can occur anywhere on the body but have a predilection for certain high-tension sites. The most common locations are:
- Earlobes – Pierced earlobes account for a significant percentage of keloids.
- Shoulders
- Chest
- Back
- Abdomen
- Sternum – Keloids may form after open heart surgery or other sternal procedures.
- Upper arms
Keloids tend to follow skin tension lines and have a tendency to form parallel to the direction of the wound. For example, keloids may orient themselves along the site of a surgical incision.
Single vs. Multiple Keloids
Keloids can occur as:
- Single keloids – One keloid scar at the site of a skin injury.
- Multiple keloids – Some individuals are prone to developing keloids and may have numerous lesions at different body sites. This is more common in darker-skinned patients.
Signs and Symptoms
In addition to their characteristic appearance, keloids may cause other signs and symptoms:
- Enlargement over time – Keloids progressively enlarge over months to years. They rarely regress spontaneously.
- Pruritus – Keloids can itch, although the degree of pruritus varies.
- Pain – Some keloids are painful, especially if superficial nerves are trapped within the scar tissue.
- Restricted mobility – Large keloids may limit movement if they form over joints. Movement of the chest wall may be impaired by massive chest keloids.
Comparing Keloids to Other Scar Types
Keloids can be distinguished from other types of scars by carefully noting differences:
Keloids vs. Hypertrophic Scars
| Keloid | Hypertrophic Scar |
|---|---|
| Grows beyond original wound boundaries | Remains confined to borders of original wound |
| Does not regress spontaneously | Often improves spontaneously over time |
| Occurs months to years after injury | Starts within 4-8 weeks of injury |
| Tends to recur after surgical excision | Less likely to recur after excision |
Keloids vs. Contracture Scars
| Keloid | Contracture Scar |
|---|---|
| Proliferative scar | Non-proliferative, mature scar |
| Elevated above skin | At level with or depressed below surrounding skin |
| Expands beyond original wound | Does not expand beyond wound edges |
| Caused by excessive collagen deposition | Caused by collagen cross-linking and skin tension |
Conclusion
Keloids have a characteristic set of clinical features that help distinguish them from other types of abnormal scarring. Hallmarks of keloids include growth beyond the original wound borders, lack of spontaneous regression, delayed onset, and a tendency to recur after treatment. Careful examination of the appearance, texture, size, location and accompanying symptoms of a scar lesion helps determine if it is a true keloid.
