Hypertrophic Scars and Keloids

A hypertrophic scar is defined as a widened or unsightly scar that does not extend beyond the original boundaries of the original injury. Hypertrophic scars appear within weeks of skin injury.
A keloid is an overgrowth of dense fibrous tissue, a scar whose size far exceeds that which would be expected from the extent and margins of an injury to the skin. Keloid, derived from the Greek chele (crab's claw), describes the lateral growth of tissue into unaffected skin.
Hypertrophic scars and keloids represent an exaggerated formation of scar tissue in response to skin injuries such as lacerations, insect bites, ear piercing, and surgical wounds.
Such scars may also result from healed inflammatory lesions (e.g., acne, chickenpox) (Fig. 30.50).
In recent years, the popularity of skin piercing procedures and tattooing has increased the frequency of these undesirable scars and has expanded the sites on the body where they may occur.
Exaggerated scars occur less frequently at the extremes of age—the very young and elderly—however, increasing numbers of presternal keloids, as well as hypertrophic scars may be seen in older age groups and result from coronary artery bypass surgery or intravenous Port-A-Caths (peripherally inserted central venous catheters) used to deliver fluids and medications.
Keloids are more likely to occur in Hispanics, Asians, and particularly individuals of African descent than in Caucasians. There is no racial preponderance noted with hypertrophic scarring.

Pathogenesis ⬆ ⬇

In susceptible individuals an overproduction of collagen becomes piled up in fibrous masses resulting in an exaggerated formation of scar tissue.
Hypertrophic scars: Scanning electron microscopy reveals flattened collagen bundles that are parallel in orientation.
Keloid: Unlike hypertrophic scar formation, the electron microscope reveals a number of distinguishing features, including randomly organized collagen fibers in a dense connective tissue matrix.

Clinical Manifestations ⬆ ⬇

Hypertrophic scars and keloids are firm, flesh-colored, tan, shiny, hairless papules, nodules, or tumors.
If lesions are inflamed or are of recent onset, they may be red (erythematous) or purple (violaceous).
Both hypertrophic scars and keloids may be tender, painful, or pruritic; however, keloids, by virtue of their excessive size, are generally more problematic and are of much greater cosmetic concern to patients.
Unlike keloids, the hypertrophic scar reaches a certain size and subsequently stabilizes or regresses, whereas keloids do not regress without treatment and tend to recur after excision.
Both hypertrophic scars and keloids tend to arise in the same anatomic locations: the sternum (Fig. 30.51), the shoulders, the deltoid region of the upper arm, and the upper back.
The most common sites on the head and neck are the earlobes, mandibular border, and posterior neck. The earlobe is typically affected secondary to earring posts (Figs. 30.52 and 30.53).

Diagnosis ⬆

The diagnosis of hypertrophic scars and keloids is made on the basis of clinical appearance.

Management

Prevention

Prevention is essential. Patients who tend to develop hypertrophic scars or keloids should be advised to discontinue or avoid repetitive skin trauma such as tattooing and skin piercing, particularly in areas that are prone to abnormal scarring such as the presternal areas and earlobes.
Conditions such as inflammatory acne and cutaneous infections should be treated promptly to prevent scarring. Despite preventive measures, keloids may form in simple clean wounds or may occur in the absence of trauma.

Treatment

Hypertrophic Scars

Intralesional corticosteroids with triamcinolone acetate (ILTAC) in varying concentrations (5 to 40 mg/mL) are injected directly into the scar (Fig. 30.54); this has been the mainstay of treatment for hypertrophic scars and keloids. Use of a 25- to 27-gauge needle at 4- to 6-week intervals often helps flatten the lesions. Additionally, these injections are also useful for diminishing itching and tenderness. Side effects from these injections include hypopigmentation, atrophy, and telangiectasias (Fig. 30.55).
Topical corticosteroids: A clear surgical tape (Cordran Tape) that is uniformly impregnated with flurandrenolide, a corticosteroid, has been shown to soften and flatten keloids over time.
Pulsed-dye lasers have been used successfully and safely on some persistent hypertrophic scars.
If they are in amenable locations, hypertrophic scars can sometimes be removed by simple excision, provided that wound closure can occur without undue tension on the surgical site.

Keloids

As described above, intralesional corticosteroid injections directly into keloids are utilized; however, there is a high recurrence rate after treatment. As with hypertrophic scars, intralesional triamcinolone, often in concentrations as high as 40 mg/mL, can help flatten keloids and diminish itching and erythema.
Such high concentrations are generally necessary for denser, more recalcitrant lesions. Similarly, complications of repeated corticosteroid injections include atrophy, telangiectasias, and pigmentary alteration.
Excision, in combination with other postoperative modalities, such as ILTAC injections, compression dressings, radiotherapy, or injected interferon, is sometimes effective.
Careful operative technique that closes surgical wounds with minimal tension is important. This is followed by postoperative injection of ILTAC 2 to 3 weeks postoperatively, followed by repeat injection in 3 to 4 weeks.
After excisional treatment alone, keloids frequently recur (more than 50% of the time); however, when excision is combined with injected steroids or other modalities, the recurrence rate may be diminished.
Laser therapy. Lasers have been used as alternatives to cold excision for keloids. As with excisional therapy, results are best when laser therapy is combined with postoperative injected steroids.
Combined modality treatment of keloids. Effective treatment may involve excision followed by pressure dressings (compression therapy) during the postoperative period.
Compression therapy is based on the finding that pressure has long been known to have thinning effects on skin. Occlusive dressings such as silicone gel sheeting may also be helpful.
Topical imiquimod (Aldara) cream: Postoperative application of imiquimod 5% cream induces local production of interferon alpha, which, in turn, is known to enhance keloidal collagenase activity and reduce the synthesis of collagen.
Other medications: In addition to topical imiquimod, other methods that are sometimes used to treat keloids and hypertrophic scars include intralesional interferon, oral verapamil, intralesional bleomycin, 5-fluorouracil, and botulinum toxin.

Helpful Hint

Intralesional corticosteroid injections must be administered cautiously to avoid overtreatment, which may result in skin atrophy, telangiectasias, and over-depressed scars.

section name header

Basics ⬇

Pathogenesis ⬆ ⬇

Clinical Manifestations ⬆ ⬇

Diagnosis ⬆