Skin ageing is a progressive process in which environmental damage determines the ultimate skin appearance.
Intrinsic ageing affects unexposed and exposed skin and is characterised by dryness, laxity, fine wrinkles, and skin atrophy.
Extrinsic ageing or photo-ageing, is the result of repeated exposure to ultraviolet (UV) light. Photo-ageing affects the sun exposed areas and is characterised clinically by fine and coarse wrinkling, roughness, dryness, laxity, and pigmentary changes. There is also an increase in the development of benign and malignant neoplasms on photo-aged skin.
Photo-ageing manifest differently in the different Fitzpatrick photo-types. Herewith the manifestations;
Light skin (photo-type 1, 2 & 3): Fine lines, deep wrinkles, hyper-pigmentation and age spots.
Dark skin (photo-type 5 & 6): Uneven skin colour, post-inflammatory pigmentation (PIH), hyper-pigmentation, scarring and excessive hair growth.
Asian skin (photo-type 4): Melasma, lentigines and dermatosis papulosis nigra.
SUN DAMAGE CLASSIFICATION BY GLOGAU
Mild (age 28-35): Few wrinkles, no keratosis.
Moderate (age 35-50): Early wrinkling, sallow complexion with early actinic keratosis.
Advanced (age 50-60): Persistent wrinkling, discolouration of the skin with telangiectasis and actinic keratosis.
Severe (age 65-70): Severe wrinkling, photo-ageing, gravitational and dynamic forces affecting skin, actinic keratosis with or without skin cancer.
SEVEN RISK FACTORS FOR PREMATURE SKIN AGING
1. Free radical attacks due to illness, pollution, stress and smoking.
2. Out of control blood sugar leads to protein glycosylation - proteins combine with sugars to form AGE’s (advanced glycation end products). Insulin resistance, high blood sugar, abdominal obesity, high blood pressure and high triglycerides all contribute to premature ageing.
3. Sluggish detoxification.
4. Chronic inflammation.
5. Impaired immune function.
6. Prolonged stress.
7. Waning hormones.
Aging and photaging: Jin Ho Chung, MD, PhDa, Valerie N. Hanft, MDb, and Sewon Kang, MDb Seoul, Korea, and Ann Arbor, Michigan
Photoaging - Mechanisms and repair: Jessica H. Rabe, MD, Adam J. Mamelak, MD, Patrick J. S. McElgunn, MD, Warwick L. Morison, MD, and Daniel N. Sauder, MD Baltimore, Maryland
Anti-ageing - Nourish your skin from the inside out: Dr. Geraldine Mitton
WHAT HAPPENS INSIDE THE SKIN?
With natural ageing, the number of active melanocytes decreases by 10% to 20%.
With photo-ageing we see hypo- and hyper-pigmentation manifesting as; mottled pigmentation, lentigines, pigmented actinic and seborrheic keratoses and pigmented basal cell carcinomas.
Ortonne J-P. Pigmentary changes of the ageing skin. Br J Dermatol 1990;122:21-8.
Older skin ‘heal better’ than younger skin after cutaneous surgery. In older patients the incision lines are less red, the scarring is less hypertrophic, and normalisation of appearance occurs more rapidly than in younger patients.
Cook JL, Dzubow LM. Aging of the skin: implications for cutaneous surgery. Arch Dermatol 1997;133:1273-7.
The free radical theory of ageing was proposed in 1954. It postulates that ageing is a result of reactions caused by free radicals.
Herman D. Extending functional life span. Exp Gerontol 1998;33:95-112.
Heavy cigarette smokers, smoking more than 50 packs a year, were 5 times more likely to be wrinkled than non-smokers. Premature wrinkling was most severe when excessive sun exposure and smoking occurred together.
A smoker’s skin takes twice as long to heal and ages 10 years quicker than a non-smoker.
Kadunce DP, Burr R, Gress R, Kanner R, Lyon JL, Zone JJ. Cigarette smoking: risk factor for premature facial wrinkling. Ann Intern Med 1991;114:840-4.
Intrinsically and extrinsically aged skin share important molecular features such as elevated MMP expression, reduced fibroblast proliferation, and reduced elaboration of new collagen. Topical treatment with 1% retinol partially reversed these changes indicating that intrinsically and extrinsically aged skin respond to retinoid treatment in an analogous manner.
Varani J, Warner RL, Gharaee-Kermani M, Phan SH, Kang S, Chung JH, et al. Vitamin A antagonizes decreased cell growth and elevated collagen-degrading matrix metalloproteinases and stimulates collagen accumulation in naturally aged human skin. J Invest Dermatol 2000;114:480-6.