Hypertrophic scar is an excessive overgrowth of fibrous connective tissue during pathological healing of a skin wound. A cosmetic defect is formed with extensive skin lesions with uneven edges, congenital predisposition, inadequate surgical care and excessive tissue tension. The scar protrudes a few millimeters above the skin, has a purple or pink color, in shape and size corresponds to the wound. Diagnosis is carried out by examination, in doubtful situations, a pathomorphological examination is prescribed. Correction of hypertrophic scars is performed by injections, methods of cryo- and laser destruction, plastic surgery.
ICD 10
L91.0 Hypertrophic scar
General information
Physiological regeneration should be completed by the formation of a normotrophic scar, which does not protrude above the skin level and eventually becomes almost invisible. However, many patients have disorders of regenerative processes, so hypertrophic scars are a serious problem for all areas of modern surgery. The visible aesthetic disadvantage and difficulties in correction explain the high relevance of hypertrophic scars, require doctors to develop new methods for their effective masking and removal.
Causes
The nature of scarring and the appearance of a healed wound is largely determined by the etiology of skin damage. For reasons of appearance, scars are post-traumatic, postoperative, formed on the site of pathological skin elements or as a result of radiation therapy. The following factors contribute to the formation of a pathological hypertrophic scar at the wound site:
- The nature of the damage. Pathological scars are more likely to occur with torn, decomposed and bitten wounds, when the traumatization of the skin does not correspond to the Langer lines. The predisposing factor is healing by secondary tension, suppuration and inflammation of the injury site.
- Excessive tension of fabrics. This situation occurs when suturing and plastic correction of a scar without skin grafting, when the patient’s own tissues are tightened to close the defect. At the point of tension, the formation of structural connective tissue is disrupted, hypertrophic phenomena occur.
- Dangerous localization. Pathological scars are mainly formed on the front surface of the neck, in the area of the earlobe. This is due to the different mechanical properties of the skin in different parts of the body, which has a significant role in the regeneration processes.
- Tendency to pathological scarring. Genetic and immune variants of predisposition to the formation of hypertrophic and keloid scars have been proven. In such patients, pathological scars are formed even in the absence of other provoking factors.
Pathogenesis
Classical wound healing lasts up to 1 year, ends with the formation of a scar. In the first 10 days, acute inflammation is observed, which in the following month leads to active fibrinolysis and the formation of loose connective tissue. For 2-3 months after skin damage, the tissues are compacted, a durable scar is formed. The final restructuring of the scar occurs 4-12 months, it is during this period that hypertrophic changes appear.
In the hypertrophic process, immature connective tissue is located in the subepidermal layer. Pathomorphologically, it is represented by thin bundles of collagen, individual elastin fibers, and an excessive amount of extracellular matrix. A large number of plasma cells are observed, but giant fibroblasts are absent. From above, the formation is covered with an even layer of epidermis.
Classification
Hypertrophic scar is one of the classic variants of scars, according to clinical and morphological systematization. In practical dermatology, other types of classification are also used to most accurately describe the features of skin regeneration and select methods for correcting pathological cases. There are several criteria for the systematization of scar changes:
- By age: immature (up to 3 months), moderately mature (3-12 months), mature (older than 1 year).
- According to the configuration: linear, arc-shaped, zigzag, star-shaped and other variants of irregular shape.
- In color: pink, purplish-red, cyanotic, whitish, pigmented.
- In size: small (up to 1 cm), medium (1-2 cm), large (up to 4.5 cm), extensive (more than 4.5 cm).
Symptoms
This type of scar begins to grow 3-4 weeks after the injury, its increase in size lasts on average 5-6 months. Hypertrophic scar has a reddish or bluish tint, in size and shape corresponds to the boundaries of the wound, rises above the surface of healthy skin by no more than 4 mm. Over time, the formation acquires a light pink or flesh tint, after 12-18 months, its partial spontaneous regression is possible.
The surface of the hypertrophic scar is uneven with protruding areas, the skin above it is matte. Its contours are clearly outlined, but the edges smoothly transition to the surrounding skin and gradually merge with them. In places of constant friction, the scar is covered with keratinized layers and small ulcers. At the same time, the patient is concerned about soreness, severe itching, wetness or discharge of blood.
Complications
Hypertrophic scars do not threaten human life and health. Their main problem is a cosmetic defect, especially when localized on the face and exposed areas of the body. Large and noticeable scars affect the psychological state of patients, cause problems with socialization, become an obstacle to building relationships with the opposite sex.
Unpleasant consequences are observed when the scar is located in the place of permanent traumatization. Due to mechanical friction, wounds and ulcers appear on its towering surface, which can become infected with the development of secondary bacterial complications. Hyperkeratosis phenomena also occur, which aggravate the unaesthetic appearance of scar tissue.
Diagnostics
With the formation of hypertrophic scars, an examination by a dermatologist and surgeon is indicated. In most situations, the diagnosis is established on the basis of a physical examination: the external characteristics of the scar, the conditions of its appearance, the presence of subjective symptoms are determined. With the consent of the patient, the affected area of the body is photographed to track the dynamics of changes. Additional diagnostic methods:
- Ultrasound of soft tissues. Sonography is prescribed to assess the thickness and depth of scar tissue, to investigate the nature and completeness of wound healing, to exclude complications.
- Pathomorphological research. To study the structure of a hypertrophic scar, light and electron microscopy, microscopic morphometry are performed. Studies are necessary in case of difficulties in differentiating different types of scars, the need to exclude other skin pathologies.
Differential diagnosis
In clinical practice, it is necessary to distinguish between hypertrophic and keloid scars, which have a great external similarity and pathomorphological signs. The keloid type of scar is indicated by the spread of connective tissue beyond the damage, continued growth for many months and even years, intense subjective sensations (itching, burning, soreness). Pathomorphologically, the keloid is characterized by atypical giant fibroblasts.
Treatment
Conservative therapy
There is no generally accepted protocol for the correction of pathological scar tissue. The treatment program is selected individually for each patient, based on the clinical features, localization, age of formation and other characteristics of hypertrophic scar. Small formations can be corrected by non-surgical techniques, the most effective of which are:
- Local compression therapy. Pressing silicone plates and elastic bandages slow down the growth of scar tissue, contribute to the formation of normotrophic scars.
- Corticosteroid injections. With small fresh scars, hormones inhibit the excessive formation of fibroblasts and collagen, slow down the growth rate of connective tissue. Injections of glucocorticoids are carried out until the scar is equal in height to the surface of the skin.
- Physical therapy. Fibrinolytic enzymes (lidase, collagenase) are used to reduce the volume of connective tissue fibers, which are introduced by electrophoresis and ultraphonophoresis.
- Cryodestruction. For non-invasive removal of hypertrophic scar, liquid nitrogen is used, which is applied to the lesion, freezes pathological tissues and destroys them. To achieve a good cosmetic effect, several sessions are held.
- Laser grinding. Correction of hypertrophic growths is performed by ablative lasers, which remove non-structural connective tissue and smooth out the contours of the scar. The fractional method of laser grinding is mainly used, which is characterized by a short rehabilitation period.
Surgical treatment
Surgical correction of scar tissue is indicated when medicinal and minimally invasive methods of treatment are ineffective. Surgical intervention is aimed at excision of pathological growths of connective tissue, elimination of excessive skin tension. Secondary wound defects are closed with the help of local or displaced skin flaps, dermotension with the use of tissue expanders.
Prognosis and prevention
Small hypertrophic scars are successfully corrected by injection, hardware or surgical techniques. With large scars and a genetic tendency to pathological regeneration, the prognosis is less favorable: complex therapy reduces the size and tuberosity of the scar, but it is often not possible to achieve normotrophy and completely hide the defect.
Prevention of pathological scarring consists in timely and qualified assistance of surgeons in case of serious injuries, adequate immobilization in the early healing period, compliance with the stages of surgical treatment. With extensive damage to the skin, from the very beginning of treatment, a consultation of a plastic surgeon is required to choose the optimal method of closing defects in order to minimize the formation of scars.