Introduction
Rhytides, or wrinkles, are visible creases or folds in the skin. Fine wrinkles are <1 mm in width and depth, while coarse wrinkles are ≥1 mm in width and depth. These are caused by progressive collagen loss, resulting in low elasticity of tissue and lower cellular reproduction. These are formed by dermal atrophy and repetitive contraction of underlying facial musculature.
Epidemiology
Skin changes in wrinkles can begin as early as the age of 30 and become more pronounced after 40. Men and women exhibit different patterns of facial wrinkling. Overall, men tend to have a greater wrinkle area than women, particularly in younger age groups. However, females show more facial wrinkles than males, particularly in the forehead region.
Lower epidermal melanin levels make Caucasians more vulnerable to premature photoaging. Conversely, Asian and Black skin possess a thicker, more compact dermis with higher pigment levels, which acts as a protective mechanism against ultraviolet (UV) damage, resulting in fewer visible wrinkles and slower photoaging compared to lighter skin types.
Pathophysiology
Skin aging is a gradual decline in skin quality caused by the combined effects of chronological aging, photoaging, hormonal changes, and environmental factors. This involves reduced fibroblast activity and decreased blood supply, leading to collagen loss, skin laxity, and wrinkle formation. Prolonged sun exposure accelerates extrinsic aging by weakening the connection between the epidermis and dermis through loss of fibrils and type VII collagen, while intrinsic aging results from internal changes in the basal cell layer that cause skin thinning and sagging.
Risk Factors
The etiology of rhytides involves both intrinsic and extrinsic factors. Intrinsic factors include aging, genetic background, hormonal status, and the presence of intercurrent diseases. Intrinsic factors also include natural changes such as decreased muscle elasticity, tone, and volume, as well as remodeling of facial bones.
Extrinsic factors involve environmental and lifestyle exposures such as ultraviolet (UV) radiation, visible light or solar irradiation (400–760 nm), air pollution, cigarette smoke, poor nutrition, and excessive alcohol consumption. Among these, smoking and UV radiation are recognized as the most significant external risk factors, while age remains the strongest determinant of facial wrinkling. Furthermore, currently smoking and lower body mass index are significantly associated with increased wrinkle formation. Women with lower educational attainment and alcohol consumption also exhibit greater facial wrinkling.
Classification
Types of Rhytides or Wrinkles
Dynamic Wrinkles
Dynamic wrinkles are due to contraction of muscles that are attached to the overlying skin. The most common locations are between the eyebrows, on the forehead, and on the cheeks near the outer corners of the eyes, or “crow’s feet”.
Static Wrinkles
Static wrinkles are due to skin damage from sun, smoking, genetics, poor nutrition, or prolonged dynamic wrinkling.
Wrinkle Folds
Wrinkle folds are caused by sagging of the facial structures that results in deep grooves between the nose and mouth known as the nasolabial groove.
Fitzpatrick and Glogau Classifications
The Fitzpatrick and Glogau classifications are the most commonly used in assessing the patient’s degree of skin damage and its appropriate type and depth of facial resurfacing modality.
The Fitzpatrick wrinkle and elastosis scale (FWS) is used for the assessment of the degree of wrinkling and elastosis in the mouth and eyes.
- Class I: Fine wrinkles with mild elastosis
- Class II: Fine to moderately deep wrinkles and moderate number of lines with distinct papular elastosis
- Class III: Fine to deep wrinkles, numerous lines with or without redundant folds with multipapular and confluent elastosis
The modified Fitzpatrick wrinkle scale (MFWS) is used to evaluate the severity of nasolabial fold wrinkling by wrinkle depth.
- Class 0: No visible wrinkle; continuous skin line
- Class 0.5: Very shallow with visible wrinkle
- Class 1: Visible wrinkle with slight indentation
- Class 1.5: Visible wrinkle with clear indentation (<1 mm wrinkle depth)
- Class 2: Moderate wrinkle; clear visible wrinkle (1-2 mm wrinkle depth)
- Class 2.5: Prominent and visible wrinkle (>2 to <3 mm wrinkle depth)
- Class 3: Deep and furrow wrinkle (-3 mm wrinkle depth)
Fitzpatrick sun-reactive skin types describe the actinically damaged skin and are used in evaluating appropriate resurfacing modalities for the patient.
- Type I: Unexposed skin is white and after 1 hour of sun exposure it always burns and never tans
- Type II: Unexposed skin is white and after 1 hour of sun exposure it usually burns and tans less than average
- Type III: Unexposed skin is white to olive and after 1 hour of sun exposure it burns minimally and gradually tans
- Type IV: Unexposed skin is light brown and after 1 hour of sun exposure it burns minimally and tans well
- Type V: Unexposed skin is brown and after 1 hour of sun exposure it very rarely burns and tans profusely
- Type VI: Unexposed skin is dark brown to black and after 1 hour of sun exposure it never burns and tans deeply
The Glogau classification system gives an objective assessment of the degree of photoaging, categorizing the patient’s skin damage and used in selection of appropriate treatment option.
- Group I (Mild): No wrinkles with early photoaging and no keratoses. This usually occurs at age 28-35 years
- Group II (Moderate): Wrinkles in motion with early to moderate photoaging and sallow color with early actinic keratoses. This usually occurs at age 35-50 years
- Group III (Advanced): Persistent wrinkling or moderate acne scarring with discoloration with telangiectasias and actinic keratoses. This usually occurs at age 50-65 years
- Group IV (Severe): Only wrinkles with severe photoaging and actinic keratoses with or without skin cancer or acne scars. This usually occurs at age 60-75 years
Types of Rhytides or Wrinkles
Dynamic Wrinkles
Dynamic wrinkles are due to contraction of muscles that are attached to the overlying skin. The most common locations are between the eyebrows, on the forehead, and on the cheeks near the outer corners of the eyes, or “crow’s feet”.
Static Wrinkles
Static wrinkles are due to skin damage from sun, smoking, genetics, poor nutrition, or prolonged dynamic wrinkling.
Wrinkle Folds
Wrinkle folds are caused by sagging of the facial structures that results in deep grooves between the nose and mouth known as the nasolabial groove.