Sun-Induced Skin Disorders

UVA vs UVB

UVA → tanning & photoaging

UVB → sunburn

UVC

removed by the ozone layer

UVA

plays a role in skin cancer and has photoaging effect

UVB

- produces most erythema (sunburn)

- reaches peak intensity between 10 AM and 4 PM

- major cause of skin cancer

- photoaging effects

- synthesis of vitamin D3 in the skin

what vitamin does UVB make

D3 in the skin

when does UVB peak

10 AM - 4 PM

can clouds and water/wet clothes stop sun from going through

no; water only reflects 5% of UVR and wet clothes allow transmission of 50% UVR

dry clothes reflecting UVR

reflect almost all UVR

how much UVR does water reflect

5%

sunburn vs suntan

burn: acute reaction to excessive UVR exposure; erythema, swelling, and pain

tan: produced when UVR stimulates melanocytes in the skin

- both are caused by UVA and UVB. darkening may be visible right after exposure

when is the max response of sunburn seen and when does it usually resolve

max response in 6-24 hours and resolves in 72 hours

suntan darkening may last how long

10-30 days

suntan and protection from cancers and photodermatoses

does NOT protect from skin cancer, photodermatoses, photoaging

what are the 2 causes of photodermatoses

photoallergy or phototoxicity

what are examples of medications that are photosensitizing

antihistamines, antidepressants, tetracyclines, HTN meds, diuretics, chemotherapy, tretinoins, anticonvulsants, griseofulvin, sulfonamides (anti-infectives)

what causes the majority of skin cancer deaths? what is the majority of skin cancers?

deaths: melanoma

majority: non-melanoma

what are the areas that skin cancers occur on

sun exposed areas of the body (face, head, neck, hands)

what are the 2 types of non-melanoma skin cancers

basal cell carcinoma (BCC) and squamous cell carcinoma (SCC)

what are the risk factors for skin cancer

- fair skin

- history of one or more serious blistering/sunburns

- blonde or red hair

- blue/green/gray eyes

- visits to the tanning salon

- history of freckling

- family Hx of melanoma

- previous h/o SCC or BCC

- excessive sun exposure

- autoimmune disease

- current use of immunosuppressant drugs

- current use of photosensitizing drugs

exclusions for use of sunscreen

- allergy to sun protective ingredients

- <6 months of age

what age is an exclusion for the use of sunscreen

< 6 months

prevention of sunburn (decreasing efficacy)

- sun avoidance

- covering clothing (dry better than wet)

- hat with 4" brim, long pants, sleeves, sunscreen products

- skin type is the primary indicator of need

minimal erythema dose (MED)

minimum UVR dose that produces clearly marginated erythema in a single exposure

sun protection factor (SPF); how is it determined, and what does a higher number mean

MED on protected skin/MED on unprotected skin

higher is more effective

what SPF is considered high protection

SPF 30 and up

what does broad spectrum mean

protection from UVA and UVB

sunscreens without broad spectrum must

carry warning

SPF of 2-14 and/or only UVB only does what

prevent sunburn, not skin cancer

sunscreens that only protect from UVB prevent what

only sunburn, not skin cancer (2-14 SPF also)

sunscreens that are 2-14 SPF prevent what

only sunburn, not skin cancer (only UVB sunscreens also)

SPF >15 may claim

may claim to reduce the risk of skin cancer and early skin aging if used as directed

length of efficacy of sunscreen; what are the names for sunscreens that stay effective for 40 mins while exercising? 80 mins?

- ability to remain effective during prolonged exercising, swimming, or sweating

- if effective 40 minutes while swimming/sweating, its water resistant

- if effective 80 minutes while swimming/sweating, its very water resistant

what does the law prohibit on the labeling of sunscreen

"waterproof, sweatproof, and sunblock"

chemical vs physical sunscreen

chemical: avoid and block the transmission of UVR to epidermis (absorb)

physical: doesnt absorb, but reflects and scatters the UVR

what are the ingredients that are chemical sunscreens

anthranilates, benzophones, cinnamates, dibenzolymethane, derivatives, salicylates

what are the ingredients that are in physical sunscreens

titanium dioxide, zine oxide

anthranilates; what is it, characteristics, and examples

chemical sunscreen ingr

- weak, UVA protection, usually in combo

- meradimate

what are the anthranilates and what kind of sunscreen are they

chemical sunscreen; meradimate

meradimate

chemical sunscreen; anthranilate (weak, UVA protection)

salicylate; what is it and characteristics

chemical sunscreen ingr

- weak and easily removed

cinnamates; what is it, characteristics, and examples

chemical sunscreen ingr

- broad spectrum, photostabilizer, do not adhere to skin well

- cinoxate, octrocrylene, octinoxate

what are the cinnamates and what kind of sunscreen are they

chemical; cinoxate, octrocrylene, octinoxate

cinoaxate, octrocrylene, and octinoxate and what kind of sunscreens

chemical; cinnamates

dibenzolymethane derivates; what is it, characteritics, and examples

chemical sunscreen ingr

- newer agent, used in combo to increase UVA coverage

- avobenzone

what are the dibenzolymethane derivatives and what kind of sunscreen is it

chemical; avobenzone

benzophones; what is it, characteristics, and examples

chemical sunscreen ingr

- UVB primarily, often found in cosmetics, commonly used bc broad spectrum and few allergic reactions

- dioxybenzone, oxybenzone, sulisobenzone

what are the benzophones and what kind of sunscreen is it

chemical; dioxybenzone, oxybenzone, and sulisobenzone

inorganic sunscreen

physical; titanium dioxide and zinc oxide

titanium dioxide and zinc oxide; what ingredients are these

physical sunscreen; broad spectrum, used on small and prominently exposed areas

application of sunscreen for adults; how much and where

~9 1/2 tsp portions (22.5 mL)

- face and neck: 1/2 teaspoon

- arms and shoulders: 1/2 teaspoon to each side of the body

- torso: 1/2 teaspoon each to front and back

- legs and tops of feet: 1 teaspoon to each side of the body

ADEs of sunburn

rash, vesicles, hives, exaggerated sunburn

2 biggest issues of sunscreen application

too little and not often enough

when to apply sunscreen and when to reapply

- apply 15-30 minutes before exposure for max effect

- reapply every 2 hours after initial application

reapply sunscreen after each episode of

swimming, towel drying, and excessive sweating

is there any safe form of UVR exposure, and how are the effects of UVR

no safe form; effects are cumulative over a pts lifetime

what is the best protection against UVR

avoidance

hyperpigmentation

area of skin darker than surrounding skin

what are the causes of hyperpigmentation

- systemic illnesses

- localized skin diseases

- endocrine imbalances (addison, cushing, thyroid disorders, pregnancy)

- inflammatory dermatoses (contact dermatitis)

- physical trauma to skin

- medications

melasma

Brownish hyperpigmentation of the face during pregnancy; "mask of pregnancy"

solar lentigines

hyperpigmentation; Numerous spots of yellowish-brown discoloration caused by years of sun exposure; often evident in elderly patients (age spots)

medications that cause hyperpigmentation

amiodarone, anticonvulsants, anitmalarial agents, antineoplastic agents, HRT, oral contraceptives, tricyclic antidepressants

treatment goals of hyperpigmentation

- dec pigmentation of affected areas

- management focuses on melanin production pathway (stopping skin cells from overproducing melanin and chem/mechan removing the top few layers of skin)

- pts must avoid minimal exposure to UVR (lifelong commitment)

OTC hyperpigmentation medications

- hydroquinone 2% (standard)

- kojic acid

- tranexamic acid

- niacinamide

- arbutin

- glycolic acid

hydroquinone; what is it and how does it work

- gold standard of OTC hyperpigmentation treatment

- inhibits melanin production in the skin

- combining with exfoliant, topical tretinoin, or corticosteroid can increase efficacy

dosing of hydroquinone; how often to apply and when/where to not apply

- topically BID

- not for damaged skin or near eyes

when should you see results of hydroquinone and if not, what to do? what happens once you reach your results

results in 2-3 months or discontinue

once reached desired benefit, reapply as often as needed to maintain

contraindications/precautions of hydroquinone

children under 12, pregnant patients, development of onchronosis

what is the age exclusion for the use of hydroquinone

under 12 years (also pregnancy and development of onchronosis)

kojic acid; what is it and what are the concentrations

hyperpigmentation agent in concentrations of 1-4%

how does kojic acid work

by inhibiting the melanin synthesis; usually combined with other agents (AHAs with or without hydroquinone)

what dosage forms are kojic acid available in

cream, soap, lotion, drops (dosing varied on the product type)

ADEs of kojic acid

contact dermatitis, stinging, erythema

transexamic acid; what is it and how does it work

hyperpigmentation agent; works by decreasing melanocyte-stimulating hormone and pigment production

when should you see topical improvement from tranexamic acid

within 2 months

what forms is tranexamic acid available in (currently)

only found as adjunct ingredient in OTC serums currently (topical)

ADEs of tranexamic acid

skin irritation (topical)

niacinamide; what is it and how does it work

hyperpigmentation and PA agent; works by preventing the transfer of melanin to keratinocytes

what is the concentration of niacinamide, and what is it a form of

2%; form of vitamin B3

when should you see results from niacinamide

within 4 weeks

product selection for hyperpigmentation is based on

the dosage form, the skin type, and the anatomic site

exclusions for SC of hyperpigmentation

- <12 years of age

- hyperpigmentation of large body surface area

- disease-induced or drug induced hyperpigmentation

- lesions that are changing in shape, size, or color

- concomitant inflammatory disorder

photoaging and who is more susceptible

- premature skin aging associated with sun exposure

- fair skin, blue/green eyes, burns easily

what are the intrinsic vs extrinsic causes of PA

intrinsic: genetically controlled skin/muscle changes, expression lines, hormonal changes

extrinsic: UVR, smoking, wind/chemical exposure

causes of photoaging (intrinsic vs extrinsic and what is it mostly attributed to)

- intrinsic (genetically controlled skin/muscle changes, expression lines, hormonal changes) and extrinsic factors (UVR, smoking, wind/chemical exposure)

- premature aged facial skin mostly attributed to cumulative UVR

clinical stages of PA; what are they, what ages, and what is seen

1: mild (20-30 years)- no wrinkles, mild pig changes

2: moderate (30-40 years)- wrinkles in motion

3: advanced (50+)- wrinkles at rest, advanced photoage

4: severe (60+)- only wrinkles, severe photoaging

treatment goals of PA

prevent/minimize photodamage with appropriate sun protection

- reverse cumulative skin damage

- protect skin from further damage

OTC pharmacologic treatments for PA

- hydroxy acids (BHA and AHAs)

- retinol and retinaldehyde (Vit A derivative)

- ascorbic acid (Vit C)

hydroxy acids; what are they

PA treatment; acts as an exfolianT and may make the skin more sensitive to sun exposure (use with SPF 30)

how to apply hydroxy acids

- apply to dry skin 10-15 minutes after cleaning face

- start gradually

- maximum BID application

- use with SPF 30 or greater

common ADEs of hydroxy acids

burning, skin lightening, dryness, BHA may be less irritating

retinol and retinaldehyde (vita A derivatives); what are they and how do they work

PA treatment: topical retinoids, increase the collagen production to decrease appearance of fine lines, improve texture/tone

what are the topical retinoids

tretinoin, isotretinoin, tazarotene, adapalene, retinol, alitretinion

what do topical retinoids do

increase the collage production to decrease the appearance of fine lines and improve the texture and tone; used to PA

how long must retinol and retinaldehyde (vit A) be used before benefit

several months

ascorbic acid (Vit C); what is it and how does it work

- OTC for PA; anti-inflammatory, skin lightening activity,

decreases skin roughness and wrinkles

- usually 3-5% topical and use for 12 weeks

what is the strength of ascorbic acid and how long is it used for for PA

3-5% topical for 12 weeks

what is the only FDA approved OTC skin bleaching product for PA, how do you apply, what are the exclusions, and when to refer

hydroquinone

- apply 2% BID

- not for <12 yo, large areas, drug induced, or lesions that have changed

- refer if no improvement in 2 months

- do not apply near eye or damaged areas

when to refer for hydroquinone

if no improvement in 2 months

how should pts apply AHA and BHA for PA

BID for 6 months

pts using products to prevent PA or hyperpig should

protect their skin using SPF 30 or higher to maintain results