OILY SKIN has developed an undeservedly bad reputation. The cool dry look on the face is valued very highly and oily skin is to be avoided at all costs. To achieve this, some people resort to blue washing soaps. Cosmetic products that purport to remove oils from the skin do brisk sales. Oil-absorbing make-up is often applied in an only temporarily successful attempt to absorb the oils.
But what are these oils and what role do they play in the health of our skin?
The oil on the surface of our skin is a complex mixture of sebum, lipids, sweat and material from the environment.
Sebum is produced by certain glands called sebaceous glands. These glands are found in the deeper layers of the skin all over the body. There are few sebaceous glands on the hands and feet and none on the palms or soles. Sebaceous glands are clustered most densely on the chest, back, face and upper arms. On the mid-back, forehead and chin the glands are most numerous - up to 900 glands per square centimetre, and are larger in size. Numerous sebaceous glands are also to be found on the genitals and in the ear canal. Most sebaceous glands open out into a hair follicle. Sebum produced by these glands is a mixture of lipids including: fatty acids, waxes, squalene and cholesterol.
Sebum has the following very important functions;
- Reduces water loss from the skin - thus slows drying
- It coats the skin and hairs acting as a lubricant to keep skin and hair supple
- Protects the skin from infection due to bacteria and fungi - sebum has weak bactericidal and fungistatic effects.
- Sebum contains a substance that produces vitamin D when exposed to ultra-violet radiation.
- Contributes to body odour
- It is colonised by the bacteria P. acnes
- Provides physical protection for the external ear canal
The production of sebum is regulated by the sex hormones (androgens). The most active of these sex hormones is testosterone and its derivatives. These hormones are manufactured in the sex glands of the male and female (ovaries in the female and testes in the male) and also by the adrenal gland. It has also been found that females produce more sebum in the week before their menses suggesting that the hormone progesterone may also play a role in stimulating sebum production.
The sebaceous glands are active from birth protecting the newborn's skin. Babies are born with a thick coat of sebum on their skin. At puberty the production of sebum increases significantly, up to five-fold in men.
As we get older less sebum is produced. This is especially true for women after menopause. This reduction in sebum production results in faster water loss through the skin leading to dry itchy skin. The reduction in sebum causes a loss of suppleness in the skin making wrinkles more likely and causing the hair to be brittle and easily broken.
Oily skin therefore is a gift to be embraced, indeed as sebum production declines it must be replenished by the application of moisturisers to the skin.
If after all of the above you are still desirous of reducing the skin's oil production do the following.
- Use a mild drying soap such as Ivory bar.
- Certain systemic medications like oestrogen-containing oral contraceptives are useful.
- Anti-androgens such as spironolactone and Diane-35 block sebum production.
Get rid of all the oils at your own risk however, as dry skin is less supple, more prone to wrinkles, itchier, more susceptible to fungal or yeast infection and ages less well.
Dr. Clive Anderson is a dermatologist and venereologist; email: yourhealth@gleanerjm.com.
