Keloid and Hypertrophic Scar Clinical Presentation
- Author: Brian Berman, MD, PhD; Chief Editor: Dirk M Elston, MD more...
Keloids and hypertrophic scars do not usually cause symptoms, but they may be tender, painful, or pruritic or they may cause a burning sensation. In addition to symptomatic relief, cosmetic concern is the primary reason patients seek medical intervention.
Origins of lesions
Keloids manifest as exaggerated growths of scar tissue, usually in areas of previous trauma. Keloids extend past the areas of trauma, projecting above the level of the surrounding skin, but they rarely extend into underlying subcutaneous tissue.
Hypertrophic scars remain limited to the traumatized area and regress spontaneously within 12-24 months, although regression may not necessarily be complete.
Clinical findings in lesions
Keloids range in consistency from soft and doughy to rubbery and hard. Studies have demonstrated how to differentiate and classify keloids according to how they feel. Early lesions are often erythematous. Lesions become brownish red and then pale as they age. Lesions are usually devoid of hair follicles and other functioning adnexal glands. Note the images below.
Once lesions occur, the clinical course varies. Most lesions continue to grow for weeks to months and others grow for years. Growth is usually slow, but keloids occasionally enlarge rapidly, tripling in size within months. Once they stop growing, keloids do not usually cause symptoms and remain stable or involute slightly.
Keloids on the ears, neck, and abdomen tend to be pedunculated. Keloids on the central chest and extremities are usually raised with a flat surface, and the base is often wider than the top.
Most keloids are round, oval, or oblong with regular margins; however, some have clawlike configurations with irregular borders. Keloids overlying a joint can contract and restrict movement.
Most patients present with 1 or 2 keloids; however, a few patients, especially patients with spontaneous keloids, have multiple lesions, as do patients who develop keloids as a consequence of acne or chickenpox.
Keloids may be distinguished from hypertrophic scars by their clawlike projections, which are absent in the hypertrophic scar.
Frequency of lesion sites
In white persons, keloids tend to be present, in decreasing order of frequency, on the face (with cheek and earlobes predominating), upper extremities, chest, presternal area, neck, back, lower extremities, breasts, and abdomen.
In black persons, the descending order of frequency tends to be earlobes, face, neck, lower extremities, breasts, chest, back, and abdomen.
In Asian persons, the descending order of frequency is earlobes, upper extremities, neck, breasts, and chest.
The exact mechanisms of keloid and hypertrophic scar pathogenesis continue to be an enigma for physicians and researchers alike, and no specific gene or set of genes has been identified; however, the increased prevalence of keloids paralleling increased cutaneous pigmentation suggests a genetic basis or, at least, a genetic linkage. Trauma to the skin, both physical (eg, earlobe piercing, surgery) and pathological (eg, acne, chickenpox), is the primary cause identified for the development of keloids. The presence of foreign material, infection, hematoma, or increased skin tension can also lead to keloid or hypertrophic scar formation in susceptible individuals.
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