Dr. Alai is an actively practicing medical and surgical dermatologist in south Orange County, California. She has been a professor of dermatology and family medicine at the University of California, Irvine since 2000. She is U.S. board-certified in dermatology, a 10-year-certified fellow of the American Academy of Dermatology, and Fellow of the American Society of Mohs Surgery.
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Most people are understandably confused when it comes to
choosing a sunscreen
because of the baffling array of available choices. Common questions about
sunscreens include
How high should the SPF be?
Should it block UVA or UVB?
Does it matter whether it is a gel, cream, or spray?
Should it be water-resistant or waterproof?
SPF stands for sun protection
factor.
The SPF numbers on a product can range from as low as 2 to as high as 60. These
numbers refer to the product's ability to screen or block out the sun's burning
rays. The SPF rating is calculated by comparing the amount of time needed to
produce sunburn on protected skin to
the amount of time needed to cause a sunburn on unprotected skin. The higher the
SPF, the greater the sun protection.
Freckles are flat, tanned circular spots that typically are the size of the head of a common nail. The spots are multiple and may develop randomly on the skin, especially after repeated exposure to sunlight. These are particularly common in people of fair complexion on upper-body skin areas like the cheeks, nose, arms, and upper shoulders. They may appear
on people as young as age 1 or 2.
Most freckles on a person's skin are usually uniform in color. On different people, freckles may vary somewhat in color -- they may be reddish, yellow, tan, light brown, brown, or black -- but they are basically slightly darker than the surrounding skin. They tend to become darker and more apparent after sun exposure and lighten in the winter months. Freckles are due to an increase in the amount of dark pigment called melanin and are not due to an increase in the total number of pigment-producing cells called melanocytes. The word
freckle comes from the Middle English freken, which, in turn, came
from the Old Norse freknur, meaning "freckled." (Some speakers of Old English and Old Norse must have had a tendency to developing freckles.)
What types of freckles are there?
There are two basic types of freckles: simple freckles and sunburn freckles. Simple freckles are usually tan, round, and small -- about the size of a common construction nail head. Sunburn freckles are often darker, have irregular jagged borders, and may be larger than a pencil eraser. Sunburn freckles are more common on the upper back and shoulders where people frequently get their most severe sunburns.
Ephelides (singular: ephelis) is the Greek word and medical term for freckle. This term refers to flat spots that are tan, slightly reddish, or light brown and typically appear during the sunny months. They are most often found
on people with light complexions, and in some families, they are a hereditary (genetic) trait. People with reddish hair and green eyes are more prone to these types of freckles. Sun avoidance and sun protection, including the regular use of sunscreen, may help to suppress the appearance of the some types of freckles.
Lentigines (singular: lentigo) comes from the Latin word for lentil and is the
medical term for certain types of darker freckles and sunburn freckles. Lentigines tend to be darker than the common freckle and do not usually fade in the winter. This kind of spot is referred to as lentigo simplex. Although occasionally lentigines are part of a rare genetic syndrome, for the most part they are just isolated and unimportant spots.
Skin cancer is the most common form of cancer
in humans. There are three main types of skin cancer; basal cell carcinoma and
squamous cell carcinoma (the nonmelanoma skin cancers), and melanoma.
Melanoma is a type of skin cancer which begins in skin cells called melanocytes and affects more than 53,600 people in the United States each year. These melanocytes can grow together to form benign moles which, after a change in size, shape, or color can be a sign of melanoma. Caused by sun exposure, early detection becomes extremely important to avoid a spread to other areas of the body. Diagnosis is confirmed through a biopsy of the abnormal skin and treatment depends on the extent and characteristics of the patient.
Moles are small skin growths that may appear flat or raised and are often tan, brown, black, reddish brown, or skin colored. They are typically about the size of a pencil eraser. There are three types of moles. Monthly skin self-exams are essential in the early detection of abnormal moles and melanomas.
Sun sensitivity (photosensitivity) is an inflammation of the skin induced by the combination of medications or substances and sunlight. The affect on the skin is redness, which looks similar to a sunburn. Generally, these reactions are either phototoxic or photoallergic. Phototoxic drugs are more common than photoallergic drugs. Symptoms of phototoxic reactions are a burning and stinging sensation and then redness. Symptoms of photoallergic reactions are itching, redness, swelling, blisters of the affected area. Treatment generally is discontinuation of the medication and topical application of creams.
Sunburn is caused by overexposure to UV radiation from the sun. UV rays can also damage the eyes. Repeated overexposure to UV rays also increases the risk for scarring, freckles, wrinkles, and dry skin. Symptoms of sunburn include painful, red, tender, and hot skin. The skin may blister, swell, and peel. Sun poisoning (severe sunburn) include nausea, fever, chills, rapid pulse, dizziness and more. Treatment for sunburn depends upon the severity. Sun protection and sunscreen for an individual's skin type is recommended to decrease the chance of sunburn.
Sunscreens are crucial for sun protection. Sun damage to the skin from exposure to ultraviolet rays is a risk factor for skin cancer and melanoma. To avoid sunburn, people should limit sun exposure during the peak hours of 10 a.m. to 3 p.m., wear protective clothing, and use a sunscreen. People with sensitive skin should use a sunscreen with an SPF of 30 or more.
Chemical peels are performed on the face, neck or hands. They can be used to:
Reduce fine lines under the eyes and around the mouth
Treat wrinkles caused by sun damage, aging and hereditary factors
Improve the appearance of mild scarring
Treat certain types of acne
Reduce age spots, freckles and dark patches due to pregnancy or taking birth control pills (melasma)
Improve the look and feel of skin that is dull in
texture and color
Areas of sun damage, which may contain pre-cancerous keratoses that appear as scaly spots, may improve after chemical peeling. Following treatment, new pre-cancerous lesions are less likely to appear.
However, sags, bulges and more severe wrinkles do not respond well to chemical peels. They may require other kinds of cosmetic surgical procedures, such as carbon dioxide laser resurfacing , a facelift , brow lif...
Most people are understandably confused when it comes to
choosing a sunscreen
because of the baffling array of available choices. Common questions about
sunscreens include 
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