- Email: [email protected]
New Prescription Products
By OSCAR E. ARAUJO, FRANKLIN P. FLOWERS, and BARBARA EVENS
very year, millions of people head for the beach, most of them wantE ing to get the darkest tan possible before they have to leave for home. Unfortunately, many of these people get severely sunburned. A painful sunburn is not the only thing to fear from the sun_, however. Sun exposure is the leading cause of skin cancer and is also responsible for irreversible premature aging of the skin. Sunburn, skin cancer, and premature aging of the skin can all be attenuated if patients are properly informed about the hazards of the sun, and also about the sunscreen proaucts and other preventive measures that are most effective.
---~ un burn____:.::_____,... Sunburn results wfien ultraviolet (UV) light alters the keratinocytes in the basal-cell layers of the epidermis, and is characterized by redness, tenderness and, in more severe cases, blistering. These symptoms don't always become evident right away; they can develop any time from 1-24 hours after exposure. Sunburn is generally considered a minor problem, and it is easily preventable with the proper use of sunscreens. However, those who have sunburn on the eyes or genitalia, or children and adults with. extensive second-degree burns, should be referred to a physician.
Oscar E. Araujo, PhD, is professor of pharmacy practice at the College of Pharmacy, and Franklin P. Flowers, MD , is assistant professor of medicine, divisio·n of dermatology, department ofnzedicine, at the College of Medici1u1, U~1iversity of Florida, Gainesville, FL '32610. Barbara Evens, RPh, is a hospital pharmacist at Venice Memori-al Hospital, Venice, FL 33595.
42
American Pharmacy Vol. NS24, No, 6, June 1984/ 362
Treatment Many products are available for relieving sunburn, but few of them are highly recommended. For example, the majority of the topical aerosol products available-such as Americaine, Solarcaine, and Unguentine-contain up to 20% benzocaine, which can cause allergic contact dermatitis. 1 Therefore, a1though these sprays may give some temporary relief, it is probably best to avoid them. If they are used, however, they should not be applied more than three or four times a day, not be used in large quantities, and not be applied over extensive areas or on raw, blistered, or damaged skin. 2 Aspirin (up to four tablets every three hours) is an excellent treatment for sunburn pain, because of its anti-inflammatory and analgesic properties. 3 Topical steroid creams, such as triamcinolone acetonide, may also provide some benefit. However, nonprescription steroid creams may actually work only as a placebo, since they contain only a low percentage of hydrocortisone. Another measure that may give relief is cold baths, which may also prevent blistering. Cold cream and lotions that contain phenol or camphor may seem helpful because they create a cooling sensation when applied to the skin, but these counterirritants may actually cause only more irritation and pain. 2
Patients should also drink plenty of fluids to avoid dehydration and possible onset of shock.
Skin Types In order to standardize the approach to using ultraviolet (UV) light as a therapy, the concept of skin types was developed (Table 1, below). These range from very light complexioned individuals, who usually have red hair and freckles and who always burn, to those whose skin is naturally dark-brown to black and who never burn. In the middle range are those who tan nicely if they expose their skin to UV light in judicious increments.
____ Sunscreens.____ Sunscreens can be classified as physical or chemical, depending on their mechanism of action. Physical sunscreens provide a physical barrier to sunlight, and include such items as beach umbrellas, hats, and protective clothing. However, patients should be warned that sitting under a beach umbrella may not always offer complete protection from the sun, because sunlight reflects off sand and water. Zinc oxide and titanium dioxide are also classified as physical sunscreens, since they work by scattering all incident light. Chemical sunscreens work by absorbing or blocking photons. 4 When applied to the skin, all of the chem-
ical sunscreens remain primarily in the stratum corneum. Since they penetrate only to the most superficial layer of the epidermis, they need to be reapplied every two to three hours in humid weather or after swimming. To determine the effectiveness of the various sunscreen products, several factors must be considered. First, a product's active ingredient should have a relatively high molar absorptivity (a measurement of the compound's ability to absorb light). In addition, Amax, the wavelength at which maximum absorption occurs, should fall in the UVB (290-320 nm) range. · Differences in pH and the solvent used in the various sunscreens can alter peak absorbance and effectiveness.!> Other factors that should be considered include the stability of the compound, the patient's skin type, and whether or not the compound is considered safe and effective by the Food and Drug Administration.
SPF Ratios Since everyone reacts to sunlight differently, testing to find out how sunscreen products will work on every type of skin is difficult. However, by measuring the minimal erythemal dose (MED), which is the smallest amount of exposure necessary for observable erythema, a ratio has been devised that compares the MED of protected skin to unprotected skin: SPF
Table 1.
_ _ Skin Tvpes and Sunscreens _ _ Complexioll
Skin type
Very fair Fair Light to medium
I II III
Medium Dark brown
IV
Black
VI
v
Burn and tan history Always burns; never tans Burns easily; tans minimally Burns moderately; tans gradually Burns minimally; always tans Rarely burns; tans very dark brown Never burns; deeply pigmented skin, which may or may not darken
American Pharmacy Vol. NS24, No. 6, June 1984/363
Recommended SPF 10-15
6-8 4-5
2-3 2-3 0
MED of sunscreen protected = ----------~~----- MED of the nonprotected skin
In recent years, companies that manufacture suntan and sunscreen products have displayed this sun protection factor (SPF) on the label of their products. The numbers usually range from 2 to 15, and help inform the consumer about the extent of protection a particular product actually offers. As an example, if a product has an SPF of 6, a person applying it could theoretically stay in the sun six times longer than he or she could without any protection. Patients should be aware that products containing para-aminobenzoic acid (PABA) can stain cloth43
ing, especially white cotton. PABAesters can also stain, but to a lesser extent. Ironically, PABA itself can be photosensitizing, and should be avoided in patients taking photosensitizing drugs. In order for sunscreen products to be as effective as possible, patients should be instructed to reapply these products before and after swimming. Individuals who are extremely sensitive to sunlight should apply the sunscreen 30 minutes prior to exposure, to allow the product to bind to the skin. By taking all of these variables into consideration-molar absorptivity, concentration, pH, solvent, stability, SPF, and patient's skin typepharmacists can help patients make intelligent decisions on suntan and sunscreen products.
Background surfaces reflect varying amounts of light. Sunbathing on light-colored surfaces, such as sand and cement, can result in a far more serious burn than sunbathing in the backyard. Water reflects some sunlight, but many of the sun's rays penetrate the water's surface, especially when the sun is directly overhead. Therefore, swimmers and scuba divers should use sunscreens whenever possible, and reapply them as often as they can. Oil-based lotions or creams should be recommended for these patients, as these products do not wash off as easily as those in a watersoluble base.
Photosensitivity Although the primary indication for sunscreens is prevention of sunburn, premature aging of the skin, and skin cancer, sunscreens can also be used in patients who have phototoxic or photoallergic reactions after exposure to sunlight. A phototoxic reaction is an interaction between a drug and UV light; the immune response is not involved. Therefore, this type of reaction ca)1 occur in anyone. A photoallergic reaction, on the other hand, requires the. formation of an antigen-antibody complex, and this
Other Measures
_Drugs That Mov Couse Photosensitivitv_
There are other measures besides sunscreens, though, that can help prevent sunburn. For example, the sun's rays are strongest between 10 am and 2 pm, and exposure during these hours should be avoided if possible. Also, in the South, the sun is much more intense than in northern regions.
Amitriptyline (Elavil) Chlorothiazide (Diuril) Chlorpromazine (Thorazine) Chlorpropamide (Diabinese) Demeclocycline (Declomycin) Furosemide (Lasix) Hydrochlorothiazide (HydroDiuril) Imipramine (Tofranil)
~4
Nalidixic Acid (Neg Gram) Promethazine (Phenergan) Sulfamethoxazole (Gantanol) Sulfamethoxazole-trimethoprim (Bactrim; Septra) Tetracycline (Achromycin) Tolazamide (Tolinase) Tolbutamide (Orinase)
American Pharmacy Vol. NS24, No. 6, June 1984/364
Phototoxicity can result after a first exposu re, while photoallergy, because it is mediated by several processes of the immune system, will not occur until re-exposure. While phototoxicity usually results in a sunbu rn-like reaction, some type of dermatitis usually develops in photoallergy. Many drugs have been implicated as ca uses of photosensitivity reactions (Table 2, p. 44). Because it is not always possible to stay out of the sun whi le taking these products, using sunscreens may be one way to help prevent these hypersensitivity reactions from occurring.
_ _The SPF of Various S unscreens__ CO"'"1I'rdal
Apl'rtlprilltr
Activr illsrcdirrrt
110111,'
:J:i"
5% PABA in 50-70% ethyl alcohol
Pn/l
1&11
10-15
Eclipse PreSIII'
I & II 1&11
10-15 8-10
2-Hydroxy-4-methoxybcnzophenone 5-sulfo nic acid
lIVAL
11
Escalol 507 + dioxybenzone
SIII'gnrd
Homomenthyl salicylate + pdimethyl aminobenzO
Aztec
11&111 11&111
_ _ _T annlng _ __
Escalol 507 in ammonium acryla te-acrylate polymer
SIII,dow"
1I 1&IV
Both sunbu rn and sunta n result from the same length UV rays (290320 om), but they come about by entirely different mechanisms. 6 While a burn affects the keratinocytes, tanning is the result of new melanin fo rmation in the epidermis, and appears a few days after exposure, usually after initial erythema . Im mediately after exposure, however, increased pigmentation can be
Physical sunscreens (Titallillm
A-Fi/
I-IV
~n
Pharmacy Vol. NS24. No 6, June 1984 365
dio:cidt, laic, iroll, zi"c oxide,
Coven/lark
ele.)
RVPnqlle
seen . This phe nomenon is known as immediate pigment darkening, and is a result of oxida tion of the melanin already present in the ski n. Then, about ten hours after ex~ posu re, mela nosomes a re tran s-
t.'/l/('
SPI-'
7
•
• 4-' 4-'
ferred from the mela nocytes into the e pidermis. However. these effects last only a few hours, and it is the production of new melanin that is responsible for true tanning. Increased melanin production can
45
be considered as a defense mechanism of the body, since melanin helps protect the underlying skin by absorbing and scattering UV light. The amount of melanin that can be produced in an individual is genetically determined. While some people produce enough melanin to give them a dark tan, others, especially fair-skinned individuals, produce very little. Because everyone's reaction to sunlight differs, manufacturers make suntan and sunscreen products that offer a wide range of protection. Table 3 (p. 45) suggests which products should be recommended to patients based on skin type. Because UV waves in the range of 290-320 nm cause both tanning and burning, it is difficult for a product to "promote tanning and prevent burning.'' Some evidence suggests that wavelengths greater than 320 nm may promote new pigment formation, more so than short-length UV rays. This theory provides the rationale for some tanning formulations: they block UV rays of wavelengths lower than 320 nm. However, most suntan products simply contain a smaller percentage of the active ingredient that's also in sunscreen products. Products containing dihydroxyacetone or iodine only stain the skin, and so offer no pro"'t ection from sunlight. Tanning oils and baby oil also provide no protection; they only help by keeping the skin from drying out.
Developing a Tan Unfortunately, nothing will speed up the tanning process. Once burning occurs, and the pigmented skin begins to peel, not only is the patient's defense against the sun decreased, but the tanning process has to begin all over again. Usually it takes about two weeks to develop a tan, and the secret lies in short, but frequent, exposures. As a rule, people can stay out in the sun for a length of time that is equal to twice their MED without getting a painful burn. For example, if you can stay outside for 30 minutes before you start to turn pink, you should be able to 46
stay out a total of one hour before burning. Consequently, if you use a sunscreen that has an SPF of 4, you should be able to stay in the sun for a total of two hours (4 x 30 min) before burning. The problem with this formula, however, lies in the difficulty of determining your true MED, since erythema may not appear immediately. As a result, most people wind up overdoing it.
Tanning 'Salons' & 'Pills' In the past few years, tanning "salons" that offer 60-second suntans have become quite popular. A typical tanning booth is three square feet, and has walls covered with fluorescent lights that emit variable amounts of short- and long-wavelenth UV light. Therefore, it is important to wear protective eye coverings. (This
precaution is necessary in the sun, too, because UV light can cause corneal damage, and may lead to cataracts.) In fact, because of the high intensity of the UV lights in these tanning booths, staring at them for even a few seconds can result in photokeratosis. Although tanning booths use timers, sunburn is still a possibility, especially in fair-skinned individuals and, of course, in anyone who stays in the booth too long. Patients with psoriasis or porphyria, or those taking photosensitizing agents, should avoid these salons. Also, patients should be made aware that if they always burn and never tan, tanning booths will not help. In short, tanning booths offer few advantages, and because the longterm effects of intense UV light exposure are harmful, it may be best to avoid them altogether. Tanning "pills," which contain beta-carotenes and canthaxanthin, a food additive used to enhance the color of foods like oranges, barbecue sauce, and pizza, have been marketed in Europe. The "pills" stain the subcutaneous fat to an orange color, not the brown that most people want. Nor do these pills protect the skin from sunlight, because they do not stimulate melanin formation. These "pills" are no longer available in the United States due to a possible link with liver qamage, but they can be purchased in Canada. Because so many sunscreens are available, it is important for the lay public, as well as physicians, to be knowledgeable about these products. In addition, because of the serious consequences of chronic exposure to the sun, sunscreens should be used regularly by anyone with fair skin. D
References 1. E. Cronin, "Contact Dermatitis," Churchill Livingston , Edinburgh, 1980. 2. C. A . Bond, in "Handbook of Nonprescription Drugs," American Pharmaceutical Association, Washington , DC. 1982. 3. W. S. Miller, F. R. Ruderman, and J. G. Smith, Arcl!il•es vf Oamntvlogy, 95, 357 (1967). 4. L. C. Harber and D. R. Bickers, "Photosensitivitv Diseases," W. B. Saunders Co., Philadelphia, 1981. 5. G. Torosian and M. A. Lemberger, joumal of tile Amaicn11 Phnnnnceutim/ Assvcinti01r, 12, 571 (1972) . 6. T. B. Fitzpatrick l.'f a/. , "Dermatology in Medicine ," 2nd Ed ., McGraw-Hill, New York, 1979.
American Pharmacy Vol. NS24, No. 6, June 1984/366
very year, millions of people head for the beach, most of them wantE ing to get the darkest tan possible before they have to leave for home. Unfortunately, many of these people get severely sunburned. A painful sunburn is not the only thing to fear from the sun_, however. Sun exposure is the leading cause of skin cancer and is also responsible for irreversible premature aging of the skin. Sunburn, skin cancer, and premature aging of the skin can all be attenuated if patients are properly informed about the hazards of the sun, and also about the sunscreen proaucts and other preventive measures that are most effective.
---~ un burn____:.::_____,... Sunburn results wfien ultraviolet (UV) light alters the keratinocytes in the basal-cell layers of the epidermis, and is characterized by redness, tenderness and, in more severe cases, blistering. These symptoms don't always become evident right away; they can develop any time from 1-24 hours after exposure. Sunburn is generally considered a minor problem, and it is easily preventable with the proper use of sunscreens. However, those who have sunburn on the eyes or genitalia, or children and adults with. extensive second-degree burns, should be referred to a physician.
Oscar E. Araujo, PhD, is professor of pharmacy practice at the College of Pharmacy, and Franklin P. Flowers, MD , is assistant professor of medicine, divisio·n of dermatology, department ofnzedicine, at the College of Medici1u1, U~1iversity of Florida, Gainesville, FL '32610. Barbara Evens, RPh, is a hospital pharmacist at Venice Memori-al Hospital, Venice, FL 33595.
42
American Pharmacy Vol. NS24, No, 6, June 1984/ 362
Treatment Many products are available for relieving sunburn, but few of them are highly recommended. For example, the majority of the topical aerosol products available-such as Americaine, Solarcaine, and Unguentine-contain up to 20% benzocaine, which can cause allergic contact dermatitis. 1 Therefore, a1though these sprays may give some temporary relief, it is probably best to avoid them. If they are used, however, they should not be applied more than three or four times a day, not be used in large quantities, and not be applied over extensive areas or on raw, blistered, or damaged skin. 2 Aspirin (up to four tablets every three hours) is an excellent treatment for sunburn pain, because of its anti-inflammatory and analgesic properties. 3 Topical steroid creams, such as triamcinolone acetonide, may also provide some benefit. However, nonprescription steroid creams may actually work only as a placebo, since they contain only a low percentage of hydrocortisone. Another measure that may give relief is cold baths, which may also prevent blistering. Cold cream and lotions that contain phenol or camphor may seem helpful because they create a cooling sensation when applied to the skin, but these counterirritants may actually cause only more irritation and pain. 2
Patients should also drink plenty of fluids to avoid dehydration and possible onset of shock.
Skin Types In order to standardize the approach to using ultraviolet (UV) light as a therapy, the concept of skin types was developed (Table 1, below). These range from very light complexioned individuals, who usually have red hair and freckles and who always burn, to those whose skin is naturally dark-brown to black and who never burn. In the middle range are those who tan nicely if they expose their skin to UV light in judicious increments.
____ Sunscreens.____ Sunscreens can be classified as physical or chemical, depending on their mechanism of action. Physical sunscreens provide a physical barrier to sunlight, and include such items as beach umbrellas, hats, and protective clothing. However, patients should be warned that sitting under a beach umbrella may not always offer complete protection from the sun, because sunlight reflects off sand and water. Zinc oxide and titanium dioxide are also classified as physical sunscreens, since they work by scattering all incident light. Chemical sunscreens work by absorbing or blocking photons. 4 When applied to the skin, all of the chem-
ical sunscreens remain primarily in the stratum corneum. Since they penetrate only to the most superficial layer of the epidermis, they need to be reapplied every two to three hours in humid weather or after swimming. To determine the effectiveness of the various sunscreen products, several factors must be considered. First, a product's active ingredient should have a relatively high molar absorptivity (a measurement of the compound's ability to absorb light). In addition, Amax, the wavelength at which maximum absorption occurs, should fall in the UVB (290-320 nm) range. · Differences in pH and the solvent used in the various sunscreens can alter peak absorbance and effectiveness.!> Other factors that should be considered include the stability of the compound, the patient's skin type, and whether or not the compound is considered safe and effective by the Food and Drug Administration.
SPF Ratios Since everyone reacts to sunlight differently, testing to find out how sunscreen products will work on every type of skin is difficult. However, by measuring the minimal erythemal dose (MED), which is the smallest amount of exposure necessary for observable erythema, a ratio has been devised that compares the MED of protected skin to unprotected skin: SPF
Table 1.
_ _ Skin Tvpes and Sunscreens _ _ Complexioll
Skin type
Very fair Fair Light to medium
I II III
Medium Dark brown
IV
Black
VI
v
Burn and tan history Always burns; never tans Burns easily; tans minimally Burns moderately; tans gradually Burns minimally; always tans Rarely burns; tans very dark brown Never burns; deeply pigmented skin, which may or may not darken
American Pharmacy Vol. NS24, No. 6, June 1984/363
Recommended SPF 10-15
6-8 4-5
2-3 2-3 0
MED of sunscreen protected = ----------~~----- MED of the nonprotected skin
In recent years, companies that manufacture suntan and sunscreen products have displayed this sun protection factor (SPF) on the label of their products. The numbers usually range from 2 to 15, and help inform the consumer about the extent of protection a particular product actually offers. As an example, if a product has an SPF of 6, a person applying it could theoretically stay in the sun six times longer than he or she could without any protection. Patients should be aware that products containing para-aminobenzoic acid (PABA) can stain cloth43
ing, especially white cotton. PABAesters can also stain, but to a lesser extent. Ironically, PABA itself can be photosensitizing, and should be avoided in patients taking photosensitizing drugs. In order for sunscreen products to be as effective as possible, patients should be instructed to reapply these products before and after swimming. Individuals who are extremely sensitive to sunlight should apply the sunscreen 30 minutes prior to exposure, to allow the product to bind to the skin. By taking all of these variables into consideration-molar absorptivity, concentration, pH, solvent, stability, SPF, and patient's skin typepharmacists can help patients make intelligent decisions on suntan and sunscreen products.
Background surfaces reflect varying amounts of light. Sunbathing on light-colored surfaces, such as sand and cement, can result in a far more serious burn than sunbathing in the backyard. Water reflects some sunlight, but many of the sun's rays penetrate the water's surface, especially when the sun is directly overhead. Therefore, swimmers and scuba divers should use sunscreens whenever possible, and reapply them as often as they can. Oil-based lotions or creams should be recommended for these patients, as these products do not wash off as easily as those in a watersoluble base.
Photosensitivity Although the primary indication for sunscreens is prevention of sunburn, premature aging of the skin, and skin cancer, sunscreens can also be used in patients who have phototoxic or photoallergic reactions after exposure to sunlight. A phototoxic reaction is an interaction between a drug and UV light; the immune response is not involved. Therefore, this type of reaction ca)1 occur in anyone. A photoallergic reaction, on the other hand, requires the. formation of an antigen-antibody complex, and this
Other Measures
_Drugs That Mov Couse Photosensitivitv_
There are other measures besides sunscreens, though, that can help prevent sunburn. For example, the sun's rays are strongest between 10 am and 2 pm, and exposure during these hours should be avoided if possible. Also, in the South, the sun is much more intense than in northern regions.
Amitriptyline (Elavil) Chlorothiazide (Diuril) Chlorpromazine (Thorazine) Chlorpropamide (Diabinese) Demeclocycline (Declomycin) Furosemide (Lasix) Hydrochlorothiazide (HydroDiuril) Imipramine (Tofranil)
~4
Nalidixic Acid (Neg Gram) Promethazine (Phenergan) Sulfamethoxazole (Gantanol) Sulfamethoxazole-trimethoprim (Bactrim; Septra) Tetracycline (Achromycin) Tolazamide (Tolinase) Tolbutamide (Orinase)
American Pharmacy Vol. NS24, No. 6, June 1984/364
Phototoxicity can result after a first exposu re, while photoallergy, because it is mediated by several processes of the immune system, will not occur until re-exposure. While phototoxicity usually results in a sunbu rn-like reaction, some type of dermatitis usually develops in photoallergy. Many drugs have been implicated as ca uses of photosensitivity reactions (Table 2, p. 44). Because it is not always possible to stay out of the sun whi le taking these products, using sunscreens may be one way to help prevent these hypersensitivity reactions from occurring.
_ _The SPF of Various S unscreens__ CO"'"1I'rdal
Apl'rtlprilltr
Activr illsrcdirrrt
110111,'
:J:i"
5% PABA in 50-70% ethyl alcohol
Pn/l
1&11
10-15
Eclipse PreSIII'
I & II 1&11
10-15 8-10
2-Hydroxy-4-methoxybcnzophenone 5-sulfo nic acid
lIVAL
11
Escalol 507 + dioxybenzone
SIII'gnrd
Homomenthyl salicylate + pdimethyl aminobenzO
Aztec
11&111 11&111
_ _ _T annlng _ __
Escalol 507 in ammonium acryla te-acrylate polymer
SIII,dow"
1I 1&IV
Both sunbu rn and sunta n result from the same length UV rays (290320 om), but they come about by entirely different mechanisms. 6 While a burn affects the keratinocytes, tanning is the result of new melanin fo rmation in the epidermis, and appears a few days after exposure, usually after initial erythema . Im mediately after exposure, however, increased pigmentation can be
Physical sunscreens (Titallillm
A-Fi/
I-IV
~n
Pharmacy Vol. NS24. No 6, June 1984 365
dio:cidt, laic, iroll, zi"c oxide,
Coven/lark
ele.)
RVPnqlle
seen . This phe nomenon is known as immediate pigment darkening, and is a result of oxida tion of the melanin already present in the ski n. Then, about ten hours after ex~ posu re, mela nosomes a re tran s-
t.'/l/('
SPI-'
7
•
• 4-' 4-'
ferred from the mela nocytes into the e pidermis. However. these effects last only a few hours, and it is the production of new melanin that is responsible for true tanning. Increased melanin production can
45
be considered as a defense mechanism of the body, since melanin helps protect the underlying skin by absorbing and scattering UV light. The amount of melanin that can be produced in an individual is genetically determined. While some people produce enough melanin to give them a dark tan, others, especially fair-skinned individuals, produce very little. Because everyone's reaction to sunlight differs, manufacturers make suntan and sunscreen products that offer a wide range of protection. Table 3 (p. 45) suggests which products should be recommended to patients based on skin type. Because UV waves in the range of 290-320 nm cause both tanning and burning, it is difficult for a product to "promote tanning and prevent burning.'' Some evidence suggests that wavelengths greater than 320 nm may promote new pigment formation, more so than short-length UV rays. This theory provides the rationale for some tanning formulations: they block UV rays of wavelengths lower than 320 nm. However, most suntan products simply contain a smaller percentage of the active ingredient that's also in sunscreen products. Products containing dihydroxyacetone or iodine only stain the skin, and so offer no pro"'t ection from sunlight. Tanning oils and baby oil also provide no protection; they only help by keeping the skin from drying out.
Developing a Tan Unfortunately, nothing will speed up the tanning process. Once burning occurs, and the pigmented skin begins to peel, not only is the patient's defense against the sun decreased, but the tanning process has to begin all over again. Usually it takes about two weeks to develop a tan, and the secret lies in short, but frequent, exposures. As a rule, people can stay out in the sun for a length of time that is equal to twice their MED without getting a painful burn. For example, if you can stay outside for 30 minutes before you start to turn pink, you should be able to 46
stay out a total of one hour before burning. Consequently, if you use a sunscreen that has an SPF of 4, you should be able to stay in the sun for a total of two hours (4 x 30 min) before burning. The problem with this formula, however, lies in the difficulty of determining your true MED, since erythema may not appear immediately. As a result, most people wind up overdoing it.
Tanning 'Salons' & 'Pills' In the past few years, tanning "salons" that offer 60-second suntans have become quite popular. A typical tanning booth is three square feet, and has walls covered with fluorescent lights that emit variable amounts of short- and long-wavelenth UV light. Therefore, it is important to wear protective eye coverings. (This
precaution is necessary in the sun, too, because UV light can cause corneal damage, and may lead to cataracts.) In fact, because of the high intensity of the UV lights in these tanning booths, staring at them for even a few seconds can result in photokeratosis. Although tanning booths use timers, sunburn is still a possibility, especially in fair-skinned individuals and, of course, in anyone who stays in the booth too long. Patients with psoriasis or porphyria, or those taking photosensitizing agents, should avoid these salons. Also, patients should be made aware that if they always burn and never tan, tanning booths will not help. In short, tanning booths offer few advantages, and because the longterm effects of intense UV light exposure are harmful, it may be best to avoid them altogether. Tanning "pills," which contain beta-carotenes and canthaxanthin, a food additive used to enhance the color of foods like oranges, barbecue sauce, and pizza, have been marketed in Europe. The "pills" stain the subcutaneous fat to an orange color, not the brown that most people want. Nor do these pills protect the skin from sunlight, because they do not stimulate melanin formation. These "pills" are no longer available in the United States due to a possible link with liver qamage, but they can be purchased in Canada. Because so many sunscreens are available, it is important for the lay public, as well as physicians, to be knowledgeable about these products. In addition, because of the serious consequences of chronic exposure to the sun, sunscreens should be used regularly by anyone with fair skin. D
References 1. E. Cronin, "Contact Dermatitis," Churchill Livingston , Edinburgh, 1980. 2. C. A . Bond, in "Handbook of Nonprescription Drugs," American Pharmaceutical Association, Washington , DC. 1982. 3. W. S. Miller, F. R. Ruderman, and J. G. Smith, Arcl!il•es vf Oamntvlogy, 95, 357 (1967). 4. L. C. Harber and D. R. Bickers, "Photosensitivitv Diseases," W. B. Saunders Co., Philadelphia, 1981. 5. G. Torosian and M. A. Lemberger, joumal of tile Amaicn11 Phnnnnceutim/ Assvcinti01r, 12, 571 (1972) . 6. T. B. Fitzpatrick l.'f a/. , "Dermatology in Medicine ," 2nd Ed ., McGraw-Hill, New York, 1979.
American Pharmacy Vol. NS24, No. 6, June 1984/366