Many people love the sun. The sun's rays make us feel good, and in the short term, it makes us look good. But our love affair isn't a two-way street: Exposure to sun causes most of the wrinkles and age spots on our faces. Consider this: One woman at age 40 who has protected her skin from the sun actually has the skin of a 30-year-old.

We often associate a glowing complexion with good health, but skin color obtained from being in the sun can actually mean accelerated effects of aging and an increased risk for developing skin cancer.

Sun exposure causes most of the skin changes that we think of as a normal part of aging. Over time, the sun's ultraviolet (UV) light damages the fibers in the skin called elastin. When these fibers breakdown, the skin begins to sag, stretch, and lose its ability to go back into place after stretching. The skin also bruises and tears more easily in addition to taking longer to heal. So while sun damage to the skin may not be apparent when you're young, it will definitely show later in life.

Changes in the skin related to sun exposure:

·         Precancerous (actinic keratosis) and cancerous (basal cell carcinoma, squamous cell carcinoma, and melanoma) skin lesions caused by loss of the skin's immune function

·         Benign tumors

·         Fine and coarse wrinkles

·         Freckles

·         Discolored areas of the skin, called mottled pigmentation

·         Sallowness: a yellow discoloration of the skin

·         Telangiectasias: the dilation of small blood vessels under the skin

·         Elastosis: the destruction of the elastic tissue causing lines and wrinkles

What is skin cancer?

Skin cancer is the most prevalent form of all cancers in the US, and the number of cases continues to rise. It is the uncontrolled growth of abnormal skin cells. While healthy cells grow and divide in an orderly way, cancer cells grow and divide in a rapid, haphazard manner. This rapid growth results in tumors that are either benign (noncancerous) or malignant (cancerous).

There are three main types of skin cancer:

·         Basal cell carcinoma

·         Squamous cell carcinoma

·         Melanoma

Basal cell and squamous cell cancers are less serious types and make up 95% of all skin cancers. Also referred to as non-melanoma skin cancers, they are highly curable when treated early.

Melanoma, made up of abnormal skin pigment cells called melanocytes, is the most serious form of skin cancer and causes 75% of all skin cancer deaths. Left untreated, it can spread to other organs and is difficult to control.

What causes skin cancer?

Ultraviolet (UV) radiation from the sun is the number one cause of skin cancer, but UV light from tanning beds is just as harmful. Exposure to sunlight during the winter months puts you at the same risk as exposure during the summertime.

Cumulative sun exposure causes mainly basal cell and squamous cell skin cancer, while episodes of severe blistering sunburns, usually before age 18, can cause melanoma later in life. Other less common causes are repeated X-ray exposure, scars from burns or disease, and occupational exposure to certain chemicals.

Who is at risk for skin cancer?

Although anyone can get skin cancer, the risk is greatest for people who have fair or freckled skin that burns easily, light eyes and blond or red hair. Darker-skinned individuals are also susceptible to all types of skin cancer, although their risk is lower.

Aside from complexion, other risk factors include having a family history or personal history of skin cancer, having an outdoor job, and living in a sunny climate. A history of severe sunburns and an abundance of large and irregularly shaped moles are risk factors unique to melanoma.

What are the signs and symptoms of skin cancer?

The most common warning sign of skin cancer is a change on the skin, typically a new mole or skin lesion or a change in an existing mole.

·         Basal cell carcinoma may appear as a small, smooth, pearly, or waxy bump on the face ears and neck; or as a flat, pink/red- or brown-colored lesion on the trunk or arms and legs.

·         Squamous cell carcinoma can appear as a firm, red nodule, or as a rough, scaly flat lesion that may itch, bleed, and become crusty. Both basal cell and squamous cell cancers mainly occur on areas of the skin frequently exposed to the sun, but can occur anywhere.

·         Melanoma usually appears as a pigmented patch or bump. It may resemble a normal mole, but usually has a more irregular appearance.

When looking for melanoma, think of the ABCD rule that tells you the signs to watch for:

·         Asymmetry: the shape of one half doesn't match the other

·         Border: edges are ragged or blurred

·         Color: uneven shades of brown, black, tan, red, white, or blue

·         Diameter: a significant change in size (greater than 6 mm)

How is it diagnosed?

Skin cancer is suspected by its appearance on the skin. The diagnosis must be confirmed with abiopsy. This involves taking a sample of the tissue, which is then placed under a microscope and examined by a dermatopathologist, a doctor who specializes in examining skin cells. Sometimes a biopsy can remove all of the cancer tissue and no further treatment is needed.

Sunlight causes your skin to produce vitamin D -- a fact that, ironically, means that sunscreen campaigns may have made millions of people chronically short of this critical nutrient, and put them at a greater risk of skin cancer, rather than reducing their risk.

Research shows that a very low level of vitamin D is a major risk factor for melanoma. This flies in the face of the idea that it is too much sun that increases your melanoma risk.

There is convincing evidence that sunlight causes skin cancer. Skin cancer can be treated and cured without serious consequences. However, in some cases the condition can be life-threatening if not diagnosed in time.

Skin cancer is an occupational concern for people who work under the sun. The risk however, may be reduced through awareness of the problem, and by taking measures to prevent exposure to sunlight.

Yes. The types of radiation include

·         visible light, which gives us the colours we see

·         infrared radiation which gives us the warmth we feel

·         ultraviolet (UV) radiation

Except in extreme situations, neither visible light nor infrared radiation from sunlight causes health problems. However, ultraviolet (UV) radiation can cause harmful effects to the skin.

There are three basic types of ultraviolet radiation:

·         UVA (long-wave UV)

·         UVB (sunburn UV)

·         UVC (short-wave UV)

Table 1 summarizes the general features of each type.

 

How does sunlight affect the skin?

When ultraviolet radiation reaches the skin, some radiation is reflected away from the surface. The remaining radiation is scattered into the tissues just beneath the skin's surface. A fraction of this radiation is absorbed by the skin's living cells.

Ultraviolet radiation absorbed by living cells damages sensitive substances that influence the skin's normal growth and appearance. Damage can result in:

·         sunburn

·         increased rate of aging of the skin

·         skin cancer

Sunburn

Sunburn is the most familiar and immediate effect of ultraviolet radiation on the skin. It is an inflammation caused by an increase in blood-flow beneath the skin. The reaction is not normally instantaneous, but reaches a bright red colour within 15 to 20 hours. The condition can be very painful and sometimes causes peeling of the skin.

Brief intense exposure can cause severe sunburn in people who are not accustomed to strong sunlight. There is evidence that this type of exposure, as well as long-term exposures, might be linked to serious forms of skin cancer later in life.

Increased Rate of Aging of the Skin

Repeated exposure to the sun's ultraviolet radiation eventually causes skin damage similar to the aging process. Patches of skin become thin and less elastic, and develop blemishes, sun freckles, and wrinkles. These changes may take many years of exposure but when they occur, the damage is irreversible.

Skin Cancer

If exposure to sunlight continues for several years, the damaged skin has an increased chance of developing one of the forms of skin cancer. Exposure to ultraviolet radiation increases the risk of developing these cancers (although it may not be the only cause of the disease). While the exact relationship is not 100% defined, it appears that intermittent (occasional) exposure and exposure during childhood and adolescence are likely important predictors for basal cell carcinoma, and cutaneous malignant melanoma. High levels of chronic exposure, such as working outdoors, is more often associated with squamous cell tumours.

The following facts also link sunlight exposure to skin cancer:

·         Most skin cancer occurs in areas of skin most heavily exposed to sunlight (ears, forehead, arms, etc).

·         Skin cancer among people who are sensitive to sunlight is more common in regions with stronger sunlight.

·         People with genetic diseases that make them more sensitive to sunlight have a greater chance of developing skin cancer.

·         Studies show that ultraviolet radiation similar to sunlight causes skin cancer in animals.

 

What types of skin cancer are linked to sunlight exposure?

Three different types of skin cancer are linked to sunlight exposure:

·         basal cell cancer

·         squamous cell cancer

·         malignant melanoma

Basal Cell Cancer

Basal cell cancer is the most common of all cancers in North America and Europe. It is usually found in areas of the skin exposed to sunlight, but sometimes occurs in other areas as well. This type of skin cancer appears as a raised, hard, red or red-grey, pearly wound often found on the forehead, eyelids, cheeks, nose, and lips. Although there is always a chance it could become serious, basal cell cancer usually does not spread. Most cases are easily treated and cured.

Squamous Cell Cancer

Squamous cell cancer occurs most frequently on the skin exposed to sunlight over long periods of time. As such, this type of skin cancer tends to develop where maximum exposure to radiation occurs - forehead, cheeks, nose, lower lip, and tops of the ears. It also usually develops in areas where the skin has been damaged by the sun - areas with blemishes or sun freckles. The blemishes develop into rough, scaly patches with small areas of open wound that do not heal. They eventually grow into larger wounds with crusts. This type of cancer can be removed with a good chance of total cure, if caught in time. It is most dangerous if it occurs on mucous membranes such as on the lip.

Malignant Melanoma

Malignant melanoma, although rarer, is the most serious of the skin cancers. It often shows itself as a mole or pigment spot that begins to bleed, grow, or change its colour, shape or texture. It usually spreads if not treated in the early stage. The exact nature of the relationship between malignant melanoma and sun light is not completely clear. However, brief intense exposure (intermittent exposure) to strong sunlight appears to increase the risk of malignant melanoma in people who are not used to strong sunlight. If caught early, malignant melanoma can be treated and cured. If treatment is delayed, it is often fatal.

 

What factors affect a person's risk?

Four main factors influence the risk of skin cancer:

·         skin pigment and ability to tan

·         heredity

·         exposure to chemicals

·         amount of exposure to sunlight

Skin Pigment and Ability to Tan

Ultraviolet radiation from sunlight affects everybody's skin to some extent, but the skin's response varies widely from person to person. Peoples' sensitivity to the sun varies according to the amount of pigment in the skin and the skin's ability to tan.

Ultraviolet radiation causes tanning in two different ways: by immediate tanning and by delayed tanning. Immediate tanning causes the skin to darken in response to UVA. This darkening begins during the period of exposure, but fades within a few hours or days. The amount of tanning increases according to the skin's natural darkness and previous amount of tanning.

Delayed tanning occurs two to three days after exposure to either UVA or UVB. It lasts from several weeks to months, and is maintained by repeated exposure to sunlight. With delayed tanning, the skin increases its production and distribution of dark pigment. The skin also becomes thicker. These changes can follow sunburning or develop gradually over a long period of repeated brief exposures to sunlight.

Some people burn easily after the first hour of sun exposure following winter or any period away from the sun. Other people, especially those with dark skin, rarely burn. This difference in reaction makes it possible to classify skin into one of six different types (see Table 2).

Table adapted from:  SunSmart Victoria (2012, Cancer Council Victoria), Australia

The risk of skin cancer from the sun generally follows the same pattern. Darker skinned people have lower risk of sun-induced skin cancer. The person most prone to skin cancer caused by sunlight tans poorly and suffers sunburn easily. Frequent and/or intense sunburn in children with fair skin and freckles has been linked to malignant melanoma later in life.

Heredity

For reasons not completely understood, people with Celtic heritage (Irish, Scottish or Northern European) have increased risk of skin cancer from the sun. Genetic diseases that affect the skin can also increase the risk. For example, albinism, a genetic condition which prevents the production of normal skin pigments, makes the skin sensitive to ultraviolet light.

Exposure to Chemicals

Exposure to certain chemicals can increase the skin's sensitivity to ultraviolet light through a process called photosensitization. Examples of such chemicals include:

·         coal tar pitch and petroleum products containing polycyclic aromatic hydrocarbons (PAHs)

·         certain printing chemicals used in photosensitive printing processes

·         certain drugs and antibiotics such as tetracyclines, sulfonamides, thiazide diuretics, chlorpromazine, oral contraceptives

·         chemicals called psoralens found naturally in certain plants, fruits and vegetables

Antibiotics must be taken internally before the skin becomes sensitive to sunlight. (Check with your physician or pharmacist is you suspect abnormal or severe reaction to sun exposure after taking new medication.) However, simple skin contact with psoralens, which are found in figs, parsnips, citrus plants, or mouldy celery, can make the skin more susceptible to sunburns in some individuals.

Experimental studies show that chemicals called "promoters" can increase the cancer-causing ability of ultraviolet radiation. On the other hand, ultraviolet radiation itself can act as a promoter. In particular, ultraviolet radiation (UVR) can increase the cancer-causing ability of chemicals from coal tar and pitch.

Amount of Exposure to Sunlight

The damaging effects of ultraviolet radiation accumulate over the years. In general, the risk of developing skin cancer increases with the amount of time spent under the sun and the intensity of radiation. The intensity of radiation varies according to the season of the year, time of day, geographic location (latitude), elevation above sea level, reflection from surfaces (e.g., white sand or concrete, water, snow), stratospheric ozone, clouds, and air pollution.

Recent studies have focused on the effects of intermittent (short-term, occasional) sun exposure in comparison to chronic (long-term) exposure. It appears that the type of exposure may influence the type of cancer that develops. For example, intermittent solar exposure may be an important factor leading to the onset of basal cell carcinoma of the skin. Childhood sun exposure may also play an important part in the development of these cancers later in adult life. The pattern for cutaneous melanoma is similar to that for basal cell carcinoma.

In contrast, the relationship between squamous cell carcinoma and solar UVR appears to be quite different. For squamous cell tumours, high levels of chronic occupational sunlight exposure, especially in the 10 years prior to diagnosis, results in an elevated risk for this cancer in the highest exposure group.

 

What is the UV Index?

 

What workers are at risk?

All outdoor workers potentially exposed to the sun's ultraviolet radiation are at risk, including:

·         agricultural workers

·         farmers

·         horticultural workers

·         maintenance workers

·         pipeline workers

·         ranchers

·         athletes

·         fishermen

·         landscapers

·         military personnel

·         police

·         ski instructors

·         brick masons

·         gardeners

·         lifeguards

·         oilfield workers

·         postal carriers

·         sailors

·         construction workers

·         greenskeepers

·         loggers

·         open-pit miners

·         railroad track workers

·         surveyors

 

How can I reduce the risk of skin cancer from sunlight?

Skin cancer is the result of decades of exposure to the sun. It is important to be aware of the risks and take precautions while under the sun from as early in life as possible. Approaches to prevent skin cancer include:

·         reducing exposure to sunlight

·         wearing protective clothing

·         using sunscreens on exposed skin

·         examining the skin regularly for suspicious spots

In the winter time, it may be advisable to the above precautions when exposed to sun for prolonged periods, especially in the presence of snow or at high altitudes.

Reducing Exposure

Workers should avoid unnecessary exposure to the sun, especially to the intense midday rays between 11:00 a.m. and 4:00 p.m. during the summer. If possible, people should plan outdoor work for early morning or late afternoon, and work in the shade as much as possible. Umbrellas, buildings, trees, canopies, etc., can protect against the direct rays from the sun. Work, and take breaks in the shade when ever possible. Set up shade structures when shade is not available. In addition, water, white sand or concrete, snow, and ice can reflect from around 10 percent to 85 percent of the sun's ultraviolet radiation. Skin may require extra protection against these indirect, reflected rays.

Workplaces can also rotate workers between site locations to help reduce UV exposure.

Wearing Protective Clothing and Sunglasses

The use of wide brim hats and clothes made from close-knit fabric can protect the skin and scalp from ultraviolet radiation. Although long-sleeved shirts and long-legged pants may not be comfortable in extremely hot weather, they do help protect the skin. Not all clothing offers the same protection. For example, a white cotton T-shirt may have an SPF of 7 while a long-sleaved denim shirt has an estimated SPF of 1700. And some fabrics like cotton lose about 50% of their SPF rating when they get wet. Workers should be informed about different fabric characteristics that effect the transmission of sunlight. Also wear wrap-around sunglasses that absorb UVA and UVB radiation.

Using Protective Sunscreens

Workers should liberally apply protective sunscreen on exposed skin 20 minutes before working in the sun, then reapply it during the periods they spend under the sun, as directed by the manufacturer's instructions (usually every two hours). Most sunscreens are colourless, invisible, and cosmetically acceptable provided they do not stain clothing or produce adverse skin reactions.

Sunscreens should be used in addition to, not instead of, working in shade and wearing suitable clothing, hats, and sunglasses. Sunscreens are not intended to extend the exposure time to sunlight, but rather to reduce the effects of sunlight when people have to be in the sun. The level of protection depends greatly on how the sunscreen is applied.

A wide variety of sunscreens are available. They all contain chemical ingredients that weaken (but do not eliminate) the effects of ultraviolet radiation. The most widely used protective chemicals are PABA (para-aminobenzoic acid) and closely related chemicals such as cinnamates, salicylates, benzophenones, or anthranilates. Some sunscreens contain only one of these protective chemicals while others may have two or more for greater reliability. Products such as baby oil, cocoa butter, or skin oils that do not have protective chemicals, do not protect against sunburn, skin aging, or skin cancer.

Where skin cancer develops

Skin cancer develops primarily on areas of sun-exposed skin, including the scalp, face, lips, ears, neck, chest, arms and hands, and on the legs in women. But it can also form on areas that rarely see the light of day — your palms, beneath your fingernails or toenails, and your genital area.

Skin cancer affects people of all skin tones, including those with darker complexions. When melanoma occurs in people with dark skin tones, it's more likely to occur in areas not normally exposed to the sun, such as the palms of the hands and soles of the feet.

Basal cell carcinoma signs and symptoms

Basal cell carcinoma usually occurs in sun-exposed areas of your body, such as your neck or face.

Basal cell carcinoma may appear as:

• A pearly or waxy bump
• A flat, flesh-colored or brown scar-like lesion

Squamous cell carcinoma signs and symptoms

Most often, squamous cell carcinoma occurs on sun-exposed areas of your body, such as your face, ears and hands. People with darker skin are more likely to develop squamous cell carcinoma on areas that aren't often exposed to the sun.

Squamous cell carcinoma may appear as:

• A firm, red nodule
• A flat lesion with a scaly, crusted surface

Melanoma signs and symptoms

Melanoma can develop anywhere on your body, in otherwise normal skin or in an existing mole that becomes cancerous. Melanoma most often appears on the face or the trunk of affected men. In women, this type of cancer most often develops on the lower legs. In both men and women, melanoma can occur on skin that hasn't been exposed to the sun.

Melanoma can affect people of any skin tone. In people with darker skin tones, melanoma tends to occur on the palms or soles, or under the fingernails or toenails.

Melanoma signs include:

• A large brownish spot with darker speckles
• A mole that changes in color, size or feel or that bleeds
• A small lesion with an irregular border and portions that appear red, white, blue or blue-black
• Dark lesions on your palms, soles, fingertips or toes, or on mucous membranes lining your mouth, nose, vagina or anus

• Signs and symptoms of less common skin cancers

  Other, less common types of skin cancer include:

  • Kaposi sarcoma. This rare form of skin cancer develops in the skin's blood vessels and causes red or purple patches on the skin or mucous membranes.

    Kaposi sarcoma mainly occurs in people with weakened immune systems, such as people with AIDS, and in people taking medications that suppress their natural immunity, such as people who've undergone organ transplants.

    Other people with an increased risk of Kaposi sarcoma include young men living in Africa or older men of Italian or Eastern European Jewish heritage.

  • Merkel cell carcinoma.Merkel cell carcinoma causes firm, shiny nodules that occur on or just beneath the skin and in hair follicles. Merkel cell carcinoma is most often found on the head, neck and trunk.
  • Sebaceous gland carcinoma. This uncommon and aggressive cancer originates in the oil glands in the skin. Sebaceous gland carcinomas — which usually appear as hard, painless nodules — can develop anywhere, but most occur on the eyelid, where they're frequently mistaken for other eyelid problems.

  When to see a doctor

  Make an appointment with your doctor if you notice any changes to your skin that worry you. Not all skin changes are caused by skin cancer. Your doctor will investigate your skin changes to determine a cause.