Our skin is one of the most important organs of the body and our main interface with the world. It protects the internal organs, helps resist bacteria and other infections, and even expresses our feelings - turning red when we blush, or pale when we are afraid.
Children's skin is often flawless, as it has not yet been toughened up by exposure to the elements, and it is rich in collagen, which makes it springy and elastic to the touch. But a child's skin is also vulnerable and needs care.
As well as forming a protective barrier against the action of physical, chemical, and bacterial agents on the deeper tissues, the skin contains the special end organs for the senses of touch, temperature, and pain, which are so important for protecting the body from harm. Another vital role of the skin is keeping the body fluids safely contained within the body. When a child or adult suffers severe burns, loss of fluids is a common cause of death.
Temperature control
The skin is also important in maintaining body temperature. When the body temperature rises, heat is lost due to vascular dilation and increased blood flow to the skin surface, making the skin glow red. When the temperature is low, blood vessels constrict to reduce blood flow and subsequent heat loss through the skin. The tiny body hairs also stand erect, causing 'goose pimples'.
Each square inch of skin also contains hundreds of sweat glands that are controlled by a heat regulation centre in the brain. These glands secrete moisture, which evaporates, cools the body surface, and helps maintain normal body temperature. The skin also acts as an excretory organ, losing salt and some toxic compounds through sweat.
Skin structure
The skin is composed of two distinct layers. The outer layer, called the epidermis or cuticle, is several cells thick and has an external layer of dead cells that are constantly shed from the surface and replaced from below by a basal layer of cells. The inner layer, called the dermis, is composed of a network of collagen and elastic fibres, blood vessels, nerves, fat globules, and the bases of hair follicles and sweat glands.
In certain places the outer layers of the skin are modified to produce the hair and nails. Sebaceous glands, sac-like glands that secrete the sebum that lubricates and softens the skin, open into the hair follicles a short distance below the epidermis surface. The skin varies in thickness from 0.5mm (0.02in) on the eyelids to 4mm (0.17in) or more on the palms and soles.
Skin diseases
The skin is prone to attack from bac-teria, viruses, fungi and chemicals in the environment, and there are a number of conditions that can affect it. The skin can also be affected by a person's general health and their emotions. Here are some of the most well-known conditions:
* Dermatitis is inflammation of the skin caused by exposure to physically or chemically irritating substances in the home or school, or from contact with vegetable poisons such as that found in poison ivy. Some children are sensitive to substances found in perfumes in soap and other cosmetics, and metals such as nickel used in cheap jewellery.
* Sunburn is caused by exposure to the ultraviolet rays in sunlight and may lead to skin cancer in later life. Because children's skin is sensitive, they burn more easily than adults, and the fairer the child's skin, the more protection they need. On hot summer days, 20 minutes exposure to the sun can cause burning. Children should always wear sunscreen on exposed areas of skin if they are playing out of doors in summer, and it can also help to wear long-sleeved tops or hats that shade the face. If children are playing or learning out of doors, they should be in the shade as much as possible.
* Impetigo is an infection of the skin with the bacteria streptococcus. It can normally be cured quickly by taking antibiotics.
* Athlete's foot and ringworm are fungal infections of the skin. Athlete's foot usually appears between the toes, with the skin becoming red, irritated, and crusty. Ringworm can appear anywhere on the skin but is often on the face and arms, as it is usually caught from infected pets. Usually there is a slightly red, raised mark on the skin, in the shape of a ring (hence the name). Both conditions are treated with anti-fungal creams.
* Urticaria or hives are weals caused by foreign proteins, or proteins to which the body is unduly sensitive. A reaction can occur whether the protein reaches the skin through the bloodstream in food or whether it is applied directly to the skin. The weals can vary from insect-bite sized lumps to large areas of raised skin. They can be incredibly itchy or may burn, but usually will have vanished completely within 36 hours.
Rashes
Diseases such as measles, scarlet fever, chicken pox and meningitis can produce skin rashes, as well as allergies to drugs, such as penicillin. A child who develops any kind of skin rash should always be seen by a doctor so the cause can be diagnosed.
