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815 > Ch. 38 Prevention of Sun Induced Disorders (Exam 2 Cut Off) > Flashcards

Ch. 38 Prevention of Sun Induced Disorders (Exam 2 Cut Off) Flashcards

1
Q

Prevention of Sun-Induced Disorders

A
  • UVR exposure is cumulative and can cause serious, long-term problems; commonly sunburn
  • can also cause premature aging, skin cancers, cataracts, and photodermatoses
  • Photodermatoses are skin disorders that can be induced or exacerbated by UVR exposure, 20+ disorders
  • Can aggravate cold sores, SLE, skin lesions, and melasma
  • Skin cancer is the most severe UVR caused disorder
  • Cumulative exposure back from childhood, even without sunburn, can increase risk of precancerous/cancerous conditions
  • Skin cancers are a significant cause of morbidity and mortality, most NMSC can be cured and melanoma is treatable if detected early
  • Avoiding excessive UVR by using sunscreen and sun-protective measures to decrease sun-induced disorders
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2
Q

Sun Disorder Pathophysiology

A
  • 3 bands: UVC, UVB, and UVA, all cause or exacerbate sun-induced disorders
  • Most UVC is from synthetic sources and is absorbed by dead cell layer of stratum corneum
  • UVB - primary inducer of skin cancer and its effects are augmented by UVA; also causes wrinkling, sunburn, elastosis, and collagen damage
  • Only therapeutic effect is Vitamin D synthesis and this isn’t necessary thanks to vitamin D in food/supplements
  • UVA also shown to suppress immune system and damage DNA which can cause photoaging, cancers, and photosensitivity reactions if exposed while taking a photosensitive agent (drug or food)
  • Sun tanning beds only have a ratio requirement of 0.05 (UVB:UVA), most emit 96% UVA and 4% UVB. Use increases risk of skin cancers and has no health benefits
  • Clouds provide little cover, white/light covered surfaces reflect UVR, UVB radiance increases by 4% with every increase of 1000 ft
  • Dry clothes (tightly woven) block most of UVR, wet clothes only block 50%
  • 95% of UVR still penetrates water and glass doesn’t block UVA at all
  • Time of day, ozone, altitude, season surface, latitude, land cover all effect UV index which is the scale used for skin damage by UV radiation
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3
Q

Sunburn and Suntan

A
  • Type/amount of radiation, thickness of skin layers, skin pigmentation and hydration, and distribution/concentration of blood vessel factor in to sunburn or suntan development
  • Sunburn involves many mediators including histamine, lysosomal enzymes, kinins, and at least one prostaglandin
  • UVR penetrates epidermis, causes inflammatory reaction, swelling of endothelium, and leaking of RBC
  • UVB believed to produce erythema by first causing damage to cell DNA, intensity peaks 12-24 hours
  • Tan is from UVR stimulating melanocytes to increase melanin production and from melanin oxidation by UVR (protective measures to diffuse UVR)
  • Doesn’t protect from skin cancer, photodermatoses, premature photoaging, and other UVR-health risks
  • Also doesn’t protect from future sunburns
  • UVA causes photooxidation and pigmentation
  • UVB stimulates melanocytes activity and increases their number, more permanent tanning effects
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4
Q

Photodermatoses

A

4 categories: immunological-mediated reactions, chemical-induced photosensitivity, defective DNA disorders, and photoaggravated disorders

  • Exact mechanism of these disorder’s development is unknown but UVB is believe to be primarily responsible
  • Photosensitivity encompasses photoallergy and phototoxicity
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5
Q

Photoallergy

A
  • Involves increase in chemically induced reactivity of skin to UVR/visible light
  • Starts antigenic reaction and usually needs at least one prior exposure
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6
Q

Phototoxicity

A
  • Also increase chemically induced reactivity to UVR
  • NOT immunologic
  • Often seen on first exposure with no drug cross-sensitivity
  • Can occur with drugs, plants, cosmetics, and soap
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7
Q

Skin Cancer

A
  • Majority of NMSC occur on most exposed areas of the body (hands, face, arms)
  • Two common types: BCC and SCC
  • Regardless of risk factors, skin cancers can develop in anyone with increased UVR exposure
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8
Q

BCC

A
  • Basal cell carcinoma
  • evasive, aggressive disorder of epidermis and dermis
  • Can cause serious damage to underlying tissue but rarely metastasizes
  • Type of NMSC
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9
Q

SCC

A
  • Found in keratinocytes
  • Grows slowly
  • Type of NMSC
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10
Q

Melanomas

A
  • Mostly comes from normal skin but 30% arise from existing nevi (moles)
  • Increase risk with family history, sun sensitivity, lots of atypical moles, previous BCC/SCC, tanning bed use, history of sun exposure and sunburns
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11
Q

Sunburn Clinical Presentation

A
  • Superficial with reactions that range from mild erythema to tender/painful edema
  • Severe reactions can sometimes produce burns that can go from partial to full thickness depth, vesicle (blister) development, bullae (many, large blisters), fever, chills, weakness, and shock
  • Shock caused by heat prostration or hyperprexia, can lead to death
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12
Q

Drug Photosensitivity Clinical Presentation

A
  • Similar to ACD - pruritic vesicles, bullae, and/or urticaria
  • Exaggerated sunburn with pruritic and possibly urticaria
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13
Q

Photodermatoses Clinical Presentation

A
  • Unique morphology

- Can include pruritis, papules, vesicles, plaques, and/or urticaria

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14
Q

Premature Aging Clinical Presentation

A
  • Wrinkling and yellowing of the skin
  • Prolonged exposure can cause elastosis
  • Pronounced drying, thickening, and wrinkling can also occur
  • Cracking, telangiectasia (spider vessels), solar keratoses (growth), and ecchymoses
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15
Q

Skin Cancer Clinical Presentation

A
  • BSS - translucent nodule with smooth surface
  • Firm to touch and ulcerated/crusted
  • Usually isolated on nose/face, but multiple can occur
  • SCC - slow growing, isolated papule or plaque on sun-exposure areas of the body
  • Melanoma: ABCDs
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16
Q

Melanoma ABCDs

A

A: Asymmetric shape
B: Border irregularity/poorly defined
C: Color variation within the same mole
D: Diameter > 6 mm

Mole with any of these characteristics or new growths/changes with these characteristics are reasons to see a dermatologist

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17
Q

Sun Disorder Prevention

A
  • Avoid sun-induced skin disorders and reactions
  • Minimize UVR exposure by using sunscreen
  • Product selection and degree of protection will vary depending on intended use and conditions of use
  • Greater risk factors relates to a greater need to avoid the sun; use sunscreen and wear protective clothing
  • Few options for sufferers of UVR-disorders
  • Lighter skin colors need higher SPF
18
Q

Sun Disorder Avoidance

A
  • Complete avoidance is best, but unrealistic
  • Wear protective clothing when outside
  • Next best option is sunscreen if the top two are rejected
19
Q

SPF

A
  • Measure of UVR protection
  • Minimal erythema dose is used to calculate SPF
  • MED: minimum UVR dose that produces clearly marginated erythema in the irradiated given in a single dose exposure
  • 2 MEDs - bright erythema, 4 MEDs - painful sunburns, 8 MEDs - blistering burn
  • Thickness and body area variance can respond differently
  • MED is ~33x more for darker complexions v.s. light
  • SPF = MED protected / MED unprotected, higher SPFs are more effective
  • SPFx longer in sun for same reaction without sunscreen
  • Based on final formulation and NOT active ingredient alone
  • None are 100% protective against UVB and increased SPF doesn’t provide significant increases in protection`
20
Q

Measures of UVA

A
  • SPF or measuring UVA is questionable, but FDA says that UVA and UVB can both be used as long as it is also used with new broad-spectrum in vitro test
  • Products that pass new test will offer higher protection against UVA and UVB (broad spectrum)
21
Q

Use of Sunscreens

A
  • FDA announced in June 2011 new requirements for non-Rx sunscreen
  • Cream based vehicles are usually more resistant to water
  • Oils, lotions, creams, gels, butters, pastes, ointments, sticks, and sprays are all acceptable dosage forms
  • Draft guidance - enforcement guide to provide information to help with labeling/testing product in light of the final rule
22
Q

Final Rule

A
  • Part of FDA’s 2011 announcement
  • Mandates all broad spectrum sunscreens pass new in vitro test for UVB AND UVA
  • Only SPF 15+ will be able to claim decreased risks of skin cancer and early skin aging if used with other skin protective measures
  • Can’t use claims of “waterproof,” “sweatproof,” and “sunblock” claims due to efficacy claims
  • If claimed to be water resistant, must list if it is for 40 minutes or 80 minutes of resistance
  • Must include standard “Drug Facts”
  • Max listed SPF value is 50+ since there is a lack of evidence that increases in SPF significantly increase protectivity
23
Q

Types of Sunscreens

A
  • Two subgroups: chemical and physical sunscreens
  • Chemical absorbs and blocks UVR transmission
  • Active ingredient absorbs 85% of radiation at wavelengths 290-320 nm, longer than that is debatable
  • Physical sunscreens are generally opaque and reflect/scatter UVR rather tan absorb, reflects/scatters at lengths of 290-777 nm, minimizes sunburns/tans
  • Final monograph includes 15 chemical agents and 2 physical agents deemed safe and effective by FDA
  • Final monograph eliminated requirement for minimal strength of sunscreens only containing a single ingredient
24
Q

Aminobenzoic Acid and Derivatives

A
  • Widely used sunscreen agent, but being replaced since its a major sensitizer
  • Name must be followed by “PABA”
  • Effective against UVB especially in hydroalcoholic base
  • Can penetrate horny layer and provide lasting protection
  • Doesn’t last submerged in water but good for sweating
  • Only recommend derivate padimate O
  • Disadvantages: contact dermatitis, photosensitvitiy, stinging, drying skin, yellow stain
  • Padimate O doesn’t stain clothes yellow
  • Avoid if allergic reaction has been experienced before
25
Q

Anthranilates

A
  • Ortho-aminobenzoic acid derivative
  • Meradimete, menthyl ester of anthranilic acid, weak UV sunscreen with max UVA absorbance
  • Combined with other products for broad coverage
26
Q

Benzophenones

A
  • 3 agents: dioxybenzone, oxybenzone, and sulsibenzone
  • Primary UVB absorbers, max: 282-290 nm
  • Extends into UVA range up to 350 or 380 nm
  • Alternative to aminobenzoic acid products
  • Oxybenzone is commonly used in cosmetics and is a significant sensitizer
  • Increased use of the agent has increased reports of sensitivity
27
Q

Cinnamates

A
  • Include cinoxate, octinoxate, and octrocrylene
  • First two have similar ranges/maxes of absorption
  • Octocrylene has a range of 250-360 nm, well into UVA range
  • Found more in products now due to broader spectrum
  • Effective photostabilizer than decreases the rate that other sunscreens degrade in the sun
  • Don’t adhere well to skin and need a vehicle to increase their substantivity
28
Q

Dibenzoylmethane Derivatives

A
  • Avobenzene is the first in this new class with effective through entire UVA range, max absorbance ~360 nm
  • Efficacy drops off sharply at 370 nm, so photosensitivity reactions in these ranges can still occur
  • Commonly used with other products for increased UVA protection
  • Easily degraded in sun, found with stabilizers in product
29
Q

Salicylates

A
  • Weak sunscreens that need high concentrations

- Don’t adhere well to skin and removed easily by sweating and swimming

30
Q

Other Chemical Sunscreens

A
  • Ensulizole doesn’t fit into above classes
  • Pure UVB sunscreen with a range of 290-320 nm
  • Ecamsule new FDA approved molecule (2006) that is water-resistant and broad spectrum
  • Used in combination octocrylene to increase stability
31
Q

Physical Sunscreens

A
  • Considered UV broad spectrum
  • Include zinc oxide and titanium dioxide
  • Often used on small, prominently exposed areas that can’t be limited to sun exposure
  • Current formulations have micro and nano sized particles to eliminate opaque stickiness
  • Also transparent for cosmetic appeal
  • Increased number of products with titanium dioxide since increased use of them in sunscreens extends them into the UVA range
  • FM allows zinc to be used alone or in combination with all other agents EXCEPT Avobenzone due to lack of efficacy data
32
Q

Sun Disorder Combination Products

A
  • FDA hasn’t set a limit on the number of products allowed in a combination
  • Each agent must contribute to the efficacy and not be included only for marketing purposes
  • Therefore each product must contribute to at least 2 of the SPF and the end SPF must be minimally equal to the number of active ingredients times 2
33
Q

Sunscreen Dosage/Administration

A
  • Inadequate amounts and frequency can lead to burns
  • Lips often neglected and their products/UVA:UVB spectrum differ, minimal SPF = 15
  • Protecting lips helps prevent dryness, burning, cold sores, and fever blisters
  • Max effectiveness: apply sunscreen to all exposed areas of the body at least as often as the label recommended
  • Apply 15-30 minutes before exposure and every 2 hours after per FDA recommendation, also reapply after every swimming, toweling, or excessive sweating episode
  • Standard for application is 2mg/cm^2, need about 1 oz (a shot glass) of sunscreen for the entire body
  • People usually use less sunscreen than necessary due to costs and amount of reapplication
  • Use higher SPF for longer, more intense exposure
34
Q

Sun Disorder Safety Considerations

A
  • Rashes, vesicles, hives, or exaggerated sunburns after using sunscreen is likely a photosensitive or allergic reaction
  • Rashes are a reason for medical referral
  • Identify sunscreen products name/ingredients if possible if previous reactions have occurred, hard since formulations change often
  • Aminobenzoic acid has the most reactions
  • Keep out of eyes
35
Q

Sunscreen in Cosmetic Products

A
  • Sunscreen products - drugs not cosmetics
  • Cosmetics with sunscreen agents will still be cosmetics as long as they make no therapeutic claims
  • If they make a sunscreen claim, must include appropriate labeling
  • Can include “for sunscreen use” optionally under directions for use
36
Q

Sun Disorder Product Selection Guidelines

A
  • Primary factors for product selection are intended use and specific patient characteristics
  • Use this information to help make product selection
37
Q

Intended Use of Sunscreen

A
  • Sunburns, photoaging, skin cancer, and photosensitivities and toxicities need higher SPF products to increase their protection (acute and long-term)
  • FDA recommends an SPF of at least 15
38
Q

Patient Factors for Sunscreen

A
  • Those not concerned with photosensitivity, photodermatoses, or skin cancer prevention have an easier time with product selection
  • Skin type and tanning history is important
  • Light skinned people should use SPF 30+, especially if they are easily burned
  • Better adherence for swimmers/sweaters
  • 1/3 of products are labeled noncomedogenic, fragrance free, or hypoallergenic
  • Noncomedogenic doesn’t worsen acne or plug pores and may be better for teens
  • Those with allergies should use fragrance free or hypoallergenic forms
  • Sensitivities more likely causes by ingredients in product other than the active ingredient itself
  • Those with normal, dry skin should avoid sunbathing, ethyl alcohol, and isopropyl alcohol since it can further dry the skin
39
Q

Sunscreen Special Populations

A
  • > 6 months have equal absorption to adults
  • Ask doctor for recommendations for kids <6 months
  • No special consideration for preggo or BF
40
Q

Sun Disorder Assessment

A
  • Preventative rather than treatment
  • Focus on intended use
  • Tend to get asked for recommendations to prevent sunburn, allow tanning, or for those on photosensitive drugs
41
Q

Sun Disorder Counseling

A
  • Ask how long current bottle has lasted to gauge patient’s use
  • Appropriate use: sunbather could easily use 1 oz every 80-90 minutes, meaning they could go through multiple bottles in a week depending on sunbathing frequency
  • Most only use one bottle per season so be sure to counsel patient on proper use
  • Wear sunglasses to protect eyes from sun damage
42
Q

Sun Disorder Evaluation

A
  • 24 hours after use if no obvious sunburn, photosensitivity, or photodermatosis eruption then the correct agent and SPF was used
  • Long term effects of UVR can take 20-30 years to become evident

815 (24 decks)

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