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.
FDA-approved photosensitizers
include Photofrin (porfimer sodium), Levulan (5-aminolevulinic acid or ALA), and Metvix (methyl aminolevulinate
[MAOP]). More drugs may become available in the
near future. Photofrin is used intravenously for internal cancers while Levulan
and Metvix are applied topically for skin therapy.
What light sources are
available, and how are they applied?
PDT light sources include laser, intense pulsed light, light-emitting
diodes (LEDs), blue light, red light, and many other visible lights (including
natural sunlight). Photosensitizer drugs may become activated by one or several
types of light. The optimal light depends on the ideal wavelength for the
particular drug used and target tissue.
The light
source needs to be directly applied to the target tissue for a specific amount
of time. For surface skin treatments, the light is easily directly applied to
the area of the skin where the photosensitizer drug has been applied (such as
face, scalp, arms, etc.). For internal cancers, delivering the light to the
desired area is more challenging. The light may be delivered through small
fiber-optic cables into the body cavity or area being treated. Sometimes, endoscopes (a
thin, lighted, elongated tube that is inserted into a body space) are used to
deliver the light into the lungs, stomach, or bladder.
How does PDT work?
PDT
works by direct injury to the target cells and tissues. This involves an
activated oxygen molecule that can injure or destroy nearby cells. By
preferentially attacking the active or abnormal cells, PDT combines a very high
success rate with good preservation of normal skin without significant risks for
scarring. Once the areas have healed following PDT, the areas are reexamined
to see if additional treatments or biopsies are needed.
PDT is a targeted treatment aimed at more rapidly dividing cells and atypical
skin growths. With regular or traditional cryosurgery (freezing with liquid
nitrogen) or burning, only the visible pre-skin cancers can be treated,
potentially leaving behind cancers that are hidden. PDT allows for treatment of
an entire area of sun damage, thereby reducing the chance that undetected pre-skin cancer cells will be left untreated.
Lung cancer kills more men and women than any other form of cancer. Eight out of 10 lung cancers are due
to tobacco smoke. Lung cancers are classified as either small cell or non-small
cell cancers.
Psoriasis is a long-term skin condition that may cause large plaques of red, raised skin, flakes of dry skin, and skin scales. There are several types of psoriasis, including psoriasis vulgaris, guttate psoriasis, inverse psoriasis, and pustular psoriasis. Symptoms vary depending on the type of psoriasis the patient has. Treatment of psoriasis may include creams, lotions, oral medications, injections and infusions of biologics, and light therapy. There is no cure for psoriasis.
Acne is a localized skin inflammation as a result of overactivity of oil glands at the
base of hair follicles. This inflammation, depending on its location, can take the form
of a superficial pustule (contains pus), a pimple, a deeper cyst, congested pores, whiteheads, or blackheads. Treatments vary depending on the severity of the acne.
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.
Common warts are skin growths causes by the human papillomavirus. There are many types of warts, including plantar warts, common hand warts, warts under the nails, mosaic wars, and flat warts. Over-the-counter treatments typically involve the use of salicylic acid products.
Rosacea is a skin disease that causes redness of the forehead, chin, and lower half of the nose. In addition to inflammation of the facial skin, symptoms include dilation of the blood vessels and pimples (acne rosacea) in the middle third of the face. Oral and topical antibiotics are treatments for rosacea. If left untreated, rhinophyma (a disfiguring nose condition) may result.
Esophageal cancer is a disease in which malignant cells form in the esophagus. Risk factors of cancer of the esophagus include smoking, heavy alcohol use, Barrett's esophagus, being male and being over age 60. Severe weight loss, vomiting, hoarseness, coughing up blood, painful swallowing, and pain in the throat or back are symptoms. Treatment depends upon the size, location and staging of the cancer and the health of the patient.
Alcoholism is a disease that includes alcohol craving and continued drinking despite repeated alcohol-related problems, such as losing a job or getting into trouble with the law.
A keloid is a scar that doesn't know when to stop. When the cells keep on reproducing, the result is an overgrown (hypertrophic) scar or a keloid. A keloid looks shiny and is often dome-shaped, ranging in color from slightly pink to red. It feels hard and thick and is always raised above the surrounding skin.
Cancer is a disease caused by an abnormal growth of cells, also called malignancy. It is a group of 100 different diseases, and is not contagious. Cancer can be treated through chemotherapy, a treatment of drugs that destroy cancer cells.
Keratosis pilaris (KP) is a common skin disorder in which small white or red bumps appear around hair follicles on the upper arms, thighs, buttocks, and cheeks. The cause of KP is unknown. There is no cure for keratosis pilaris, and the condition may resolve on its own. Gentle exfoliation, professional manual extraction, chemical peels, and microdermabrasion, along with topical products, are the best treatments for this condition.
Actinic keratoses are rough, scaly patches of skin that are considered precancerous and are due to sun exposure. Prevention is to cut sun exposure and wear sunscreen.
Barrett's esophagus occurs as a complication of chronic gastroesophageal reflux disease (GERD), primarily in white males. GERD refers to the reflux of acidic fluid from the stomach into the esophagus (the swallowing tube), and is classically associated with heartburn.
Smoking is an addiction. More than 430,000 deaths occur each year in the U.S. from smoking related illnesses. Secondhand smoke or "passive smoke" also harm family members, coworkers, and others around smokers. There are a number of techniques available to assist people who want to quit smoking.
Scar formation is a natural part of the healing process after injury. The depth and size of the wound incision and the location of the injury impact the scar's characteristics, but your age, heredity and even sex or ethnicity will affect how your skin reacts.
Age-related macular degeneration (AMD) is a disease that gradually destroys the central vision. In people over 60, AMD is a leading cause of vision loss. Wet AMD occurs when abnormal blood vessels behind the retina start to grow under the macula, leaking blood and fluid and causing rapid vision loss. In dry AMD, light-sensitive cells slowly break down in the macula, resulting in gradual vision loss. Pain is not associated with either form of AMD.
Wrinkles, whether they be fine line or deep furrows, typically appear on areas of the body that receive a high amount of exposure to the sun. Smoking, light skin type, hairstyle, the way you dress, your occupational and recreational habits, and heredity are all factors that promote wrinkling. Medical treatments for wrinkles include antioxidants, moisturizers, alpha-hydroxy acids, and vitamin A acid. Cosmetic procedures that treat wrinkles include dermabrasion, microdermabrasion, glycolic acid peels, laser resurfacing, Botox, and fillers.
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.
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