Getting under your skin
Posted on 11 April 2019
There’s more to your skin than meets the eye. We go beneath the surface.
As your body’s first line of defence, your skin protects your overall health. “The skin is essentially a barrier,” explains Dr Ilsa Orrey, a dermatologist at Mediclinic Constantiaberg. “It protects your body from a wide range of environmental onslaughts – including sun/ UV radiation and invasion of micro-organisms, such as bacteria.”
WHAT THE SKIN DOES
The largest organ in the body, the skin houses all your body parts. “It also prevents loss of fluids, such as water,” says Dr Orrey. “Some substances, mainly waste products, such as ammonia and salt, are excreted in sweat. Others can be absorbed through the skin, including certain medicines and hormone patches. It also transmits sensations such as heat, cold and pain to the brain, and protects it from injury. It helps in the regulation of temperature of the body, and produces essential substances, such as Vitamin D.” It also plays an important part in immune regulation, and faciliates wound healing.
The skin is divided into three separate layers known as the epidermis, dermis and subcutis – also known as the hypodermis – which work together to ensure effective overall functioning and protection.
As the outer layer of the skin, the epidermis provides a protective barrier against the environmental elements. It consists mainly of cells called keratinocytes, made from the tough protein keratin. These cells form several layers that constantly grow outwards as the exterior cells die and flake off. Beneath the epidermis lies the dermis, a thicker layer which gives your skin its integrity, strength and elasticity. It’s home to the blood vessels, glands and hair follicles, along with nerves and their receptors. The hypodermis, a specialised layer of fat and fibrous tissue, cushions your body from external trauma, insulates it from the cold and stores energy in the form of fat.
AVOIDING RISK FACTORS
Considering your skin’s protective function, caring for it is vital. Yet it’s easily damaged, which can lead to injury and infection. Excessive washing, heat, cold, UV radiation and trauma can all harm the skin, explains Dr Orrey. “Skin trauma can be caused by excessive scrubbing, exfoliation or chemical peels, application of harmful allergenic substances especially creams, over- or under-hydration and some ingested drugs or foods that can cause allergic reactions.
WHEN TO SEE A DERMATOLOGIST
According to Dr Orrey, the following skin symptoms need medical attention:
▶ skin rash that does not clear
▶ itchy skin
▶ dry skin
▶ non-healing sore
▶ painful nodules
▶ new lesions that appear on the skin that look different from the ones that were there before
▶ any lesion that changes colour, especially to black
▶ any lesion that enlarges rapidly
▶ blistering sunburn
In small doses, the ultraviolet (UV) radiation from the sun produces Vitamin D, which helps keep bones and muscles strong. Yet sunscreen is always a must. “Contrary to popular disinformation, applying sunscreen does not lower the production of Vitamin D,” says Dr Orrey. When you spend extended periods in the sun without adequate skin protection, its UV radiation can penetrate the skin and harm your health. In severe cases, the build-up of skin damage can eventually lead to mutation of skin cells, and ultimately cancer. UV radiation is in fact classified as a “complete carcinogen” – one that affects tumour cells in all stages of their development, causing cancer. Cancer begins when normal cells change and grow uncontrollably.
Dr Orrey explains the process:
▶ UV radiation directly damages the DNA of the skin cells in the bottom layer – the basal layer – of the epidermis. These are the cells that produce new skin cells every 28 days.
▶ Most skin cells that have been damaged by UV radiation are able to repair their DNA by splicing out the defective DNA. This is because cells have mechanisms to respond to and repair DNA damage within the cell before they continue dividing. If DNA damage is too severe, the cells kill themselves o , preventing DNA damage being transferred to the daughter cells.
▶ However, with time this ability is lost.
▶ When this happens, the cell produces abnormal o spring which eventually become cancerous cells.
UNDERSTANDING ULTRAVIOLET RADIATION AND SKIN CANCER
Dr Orrey explains these risk factors:
Skin can be damaged by excessive washing, especially with antibacterial soaps as these destroy the good bacteria on the skin that prevent the overgrowth of harmful bacteria. It’s best to use gentle cleansers.
▶ Sunburn damages the DNA of the skin cells and predisposes you to skin cancer later in life.
▶ Excessive dehydration of the skin can weaken the skin barrier allowing harmful organisms to enter.
▶ Exposure to cold can cause frostbite or chilblains, which damage the skin and cause pain.
▶ Exposure to heat or boiling water can cause burns of various degrees causing scarring.
▶ Mechanical damage such as trauma from tattooing or chemical peels damage the skin. “Patients with skin conditions like eczema, psoriasis or ichthyosis have generally weakened skin barriers.”
WORDS: GILLIAN KLAWANSKY