The structure of the skin

The skin is the largest organ in the body, with a surface area of 2m²,  and has multiple functionsⁱ. The skin is composed of three layers:

• the epidermis outer layer
• the dermis middle section
• the deeper hypodermis or subcutaneous fatty layer[i]

The skin has three main functions:

• Protection
• Thermoregulation
• Sensation.[i]

 
The prime function of the epidermis is to:

• Act as a physical and biological barrier to the external environment
• Prevent penetration by irritants and allergens.
• Prevent the loss of water and maintains internal homeostasis.[ii]

 
The dermis forms the inner layer of the skin and is much thicker than the epidermis (1-5mm); its primary functions are:

• Protection
• Cushioning the deeper structures from mechanical injury
• Providing nourishment to the epidermis
• Playing an essential role in wound healing [iii].

 
The hypodermis consists mainly of fat with blood vessels and nerves running through it and provides²:

• Structural support for the skin
• Insulation from the cold
• Aid in shock absorption

 

Effects of ageing on the skin

 
With advancing age, the main functions are increasingly impaired. Changes occur in the epidermis, dermis and hypodermis, leading to thin, dry and sagging skin. At the same time, loss of structure and integrity diminishes the skin’s ability to protect the body and detect changes in temperature and pressure. Ageing skin is:
 

• more fragile
• more prone to
  • infection
  • trauma
  • tears
  • pressure ulcers[i].

Moisture balance and the skin

The skin provides an effective barrier against excessive fluid loss and bacterial invasion[i], but with prolonged contact to moisture, the barrier function can be lost. Moisture-associated skin damage (MASD) can be caused by perspiration, urine or faeces, wound exudate or stomal output.
Specifically, incontinence associated dermatitis (IAD) is a higher risk in older people where the epidermal thickness has reduced, increasing the risk of skin breakdown. Urinary and faecal incontinence is also most prevalent in this age group[ii].
Effects of MASD on the skin

• Maceration
• Inflammation
• Skin breakdown
• Bacterial and fungal infections
• Friction/shear forces
• Pressure ulcers

How to care for the skin

• Cleanse the skin daily
• Avoid harsh soaps and cleansers, use products that are pH balanced to the skin
• Do not rub or use harsh cloths to wash
• Pat dry after washing
• Use a prescribed emollient to relieve dry skin
• Apply a skin protector at a frequency in line with product instructions where required
• Use a barrier product to protect areas of skin affected by MASD [i]

  
 

References: 

1. Hughes E (2001) Skin: its structure, function and related pathology. In: Hughes E, Van Onselen J (eds) Dermatology Nursing: A Practical Guide. Edinburgh: Churchill Livingstone.
2. Lawton S (2019) Skin 1: the structure and functions of the skin. Nursing Times [online]; 115, 12, 30-33.
3. Cork MJ (1997) The importance of skin barrier function. Journal of Dermatological Treatment; 8: Suppl 1, S7-S13.
4. White R, Butcher M (2005) The structure and functions of the skin. In: White R (ed) Skin Care in Wound Management: Assessment, Prevention and Treatment. Aberdeen: Wounds UK.
5. Nigam Y, Knight J (2017) Anatomy and physiology of ageing 11: the skin. Nursing Times [online]; 113: 12, 51-55.
6. Coorcoran E, Woodward S. Incontinence-associated dermatitis in the elderly: treatment options. Br J Nurs. 2013; 22(8): 450-457
7. Van Damme N, Van den Bussche K, De Meyer D, Van Hecke A, Verhaeghe S, Beeckman D. Independent risk factors for the development of skin erosion due to incontinence in nursing home residents: results from a multivariate binary regression analysis. Int Wound J. 2017; 14(5):801-810
8. Beeckman D, Campbell J, Campbell K et al. Incontinence-associated dermatitis: moving prevention forward. Proceedings from the Global IAD Expert Panel. Wounds International. 2015.