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skin aging (includes aging of skin appendages)

Also see dermatoheliosis. Pathology: Age-related changes in skin: 1) increased wrinkling 2) atrophy of sweat glands & sebaceous glands 3) decreased number & growth of hairs 4) xerosis 5) changes in epidermis a) epidermis thins with age b) stratum corneum looses basket-weave pattern - becomes thin & compact & less effective barrier c) diminished epidermal turnover - reduced mitotic rate of epidermal basal cells - increased time of epidermal wound healing d) decreased number & function of melanocytes - skin pallor e) diminished number of Langerhans cells (40-50%) - decreased delayed hypersensitivity f) decreased surface area of basement membrane - shortened & attenuated rete ridges g) decreased production of vitamin D h) decreased sebum production 6) changes in dermis a) dermis thins with age 20% b) loss of papillary dermis leading to a decrease in volume & loss of rete ridges c) diminished number of fibroblasts* 1] decreased proteoglycans, collagen, elastin - decreased strength & elasticity of skin 2] diminished production of type 1 procollagen by fibroblasts occurs with chronological aging of human skin via downregulation of the TGF-beta/Smad/CTGF axis [6] 3] decrease in elastin fibers [10] 4] increase in collagen cross-links 5] it has been proposed that skin aging is caused by the loss of papillary fibroblasts, which affects a] skin elasticity (decreased skin elasticity) b] matrix production & degradation c] epidermal interaction d] basement membrane homeostasis [7] d) diminished number of blood vessels & capillaries - impaired thermoregulation, response to injury e) loss of hydration f) loss of elasticity [5] g) diminished number of mast cells - decreased immediate hypersensitivty h) diminished nerve endings (30%) - decreased sensation, increased pain threshold 7) decreased subcutaneous fat 8) decreased skin temperature [5] 8) cyclo-oxygenase 2 (COX2) may play a role [11] - COX2 is elevated in aged skin & photoaged skin - COX2 is higher in photoaged skin than normal aged skin 9) barrier function of aged skin is less effective than younger skin [15] 10) delayed wound healing Age-related changes in skin appendages: [3] 1) hair loss a) androgen-dependent (male-balding) b) involutional alopecia - begins after age 40 - decrease in hair shaft diameter - decrease in number of hairs - loss of hair follicles 2) graying of hair a) loss of functional melanocytes in hair bulb b) by age 50, 1/2 of all body hairs become gray 3) eyebrow, ear & nasal hair coarsen & get longer, especially in men 4) nail plate thickness & growth rate decrease with age - nails become more brittle 5) sebaceous glands hypertrophy with age 6) sebum production diminishes with age 7) apocrine & eccrine glands decrease in density & accumulate lipofuscin Age-related skin lesions 1) seborrheic keratosis 2) cherry anigiomas 3) nevi may involute or disappear by the 6th or 7th decade of life The number of senescent fibroblasts* increases exponentially in the skin of aging baboons, reaching > 15% of all cells invery old individuals. [1] * determined by: 1) shortened telomeres 2) activated ataxia-telangiectasia mutated kinase 3) heterochromatinized nuclei Clinical manifestations: - aged skin is thin & inelastic, tearing easily [15] - aged skinrecovers more slowly from mechanical depression than younger skin - women have thinner skin then men - aged skin is dry, especially after frequent washing with - pigmentation is uneven due to melanocyte activation (melanosis) & inactivation (guttate hypomelanosis) - in genetically predisposed elderly: - telangiectases & cherry angiomas - seborrhoeic keratoses * images [15] Differential diagnosis: - dermatoheliosis - coarse epidermal folds - diffuse pigmentation or 'bronzing' - solar lentigo - elastosis - solar purpura - telangiectasias Complications: - increased risk of Herpes zoster - chronic onychomycosis & Tinea pedis - asteatotic eczema - also see dermatologic disorders in the elderly Management: - regular use of emollients [5] - sunscreen, protective clothing - topical retinol (0.4%) 3 times/week improves temporarily clinical signs of naturally aged skin [4] - alpha-hydroxy acids & beta-hydroxy acids may have some benefit [5]

Related

dermatoheliosis (photoaging, skin aging) dermatologic disorders in the elderly skin

General

age-related physiological changes

References

  1. Herbig U, Ferreira M, Condel L, Carey D, Sedivy JM. Cellular senescence in aging primates. Science. 2006 Mar 3;311(5765):1257. Epub 2006 Feb 2. PMID: 16456035
  2. Gilchrest BA, Aging of the Skin, In: Principles of Geriatric Medicine, 4th ed,, Hazzard et al (eds), McGraw-Hill, NY, 1999, pg 573-602
  3. Freeman AK and Gordon M, Dermatologic diseases and problems, In: Geriatric Medicine: An Evidence-Based Approach, 4th ed, Cassel CK et al (eds), Springer-Verlag, New York, 2003
  4. Kafi R et al, Improvement of naturally-aged skin with vitamin A (retinol) Arch Dermatolo 2007, 143:606 PMID: 17515510
  5. Medical Knowledge Self Assessment Program (MKSAP) 15, 16, 17, 18. American College of Physicians, Philadelphia 2009, 2012, 2015, 2018.
  6. Quan T et al. Reduced expression of connective tissue growth factor (CTGF/CCN2) mediates collagen loss in chronologically aged human skin. J Invest Dermatol 2010 Feb; 130:415. PMID: 19641518
  7. Janson DG et al. Different gene expression patterns in human papillary and reticular fibroblasts. J Invest Dermatol 2012 Nov; 132:2565 PMID: 22696053
  8. Uitto J. The role of elastin and collagen in cutaneous aging: intrinsic aging versus photoexposure. J Drugs Dermatol. 2008 Feb;7(2 Suppl):s12-6. PMID: 18404866
  9. Yaar M, Gilchrest BA. Skin aging: postulated mechanisms and consequent changes in structure and function. Clin Geriatr Med. 2001 Nov;17(4):617-30, v. PMID: 11535419
  10. Geriatric Review Syllabus, 8th edition (GRS8) Durso SC and Sullivan GN (eds) American Geriatrics Society, 2013
  11. Habib MA et al. Comparative immunohistochemical assessment of cutaneous cyclooxygenase-2 enzyme expression in chronological aging and photoaging. Photodermatol Photoimmunol Photomed 2014 Feb; 30:43 PMID: 24393208
  12. Beer KR Combined treatment for skin rejuvenation and soft-tissue augmentation of the aging face. J Drugs Dermatol. 2011 Feb;10(2):125-32. Review. PMID: 21283916
  13. Farage MA, Miller KW, Elsner P, Maibach HI. Characteristics of the Aging Skin. Adv Wound Care (New Rochelle). 2013 Feb;2(1):5-10. Review. PMID: 24527317
  14. Farage MA, Miller KW, Berardesca E, Maibach HI. Clinical implications of aging skin: cutaneous disorders in the elderly. Am J Clin Dermatol. 2009;10(2):73-86. Review. PMID: 19222248
  15. DermNet NZ. Ageing skin (images) http://www.dermnetnz.org/site-age-specific/ageing.html
  16. Blume-Peytavi U, Kottner J, Sterry W et al Age-Associated Skin Conditions and Diseases: Current Perspectives and Future Options. Gerontologist. 2016 Apr;56 Suppl 2:S230-42. Review. PMID: 26994263