Lecture 17: Dermatology II Flashcards
Acne
● Inflammatory skin disease affecting pilosebaceous glands ● Common on the face, back, chest, shoulders/arms, neck ● Most prevalent during adolescence ● Often correlates with onset of puberty ● Affects 85% of 15-24 year-olds ● Impacts quality of life ● Physical scarring ● Emotional impact
Acne – Pathophysiology
1. Hormonal (androgenic) trigger ▪Associated with puberty; genetic risk 2. Sebum production 3. Altered keratinization/ Plugged duct 4. Propionibacterium acnes (P. acnes) follicular colonization ▪Break down sebum → irritating free fatty acids 5. Release of inflammatory mediators 6. Local tissue injury 7. Comedones → papules/pustules → nodules
Acne Pathophysiology
● Pilosebaceous unit in the dermis
○ Hair follicle + sebaceous gland
○ Connected to skin surface by duct lined with epithelial cells
■ Hair shaft passes through
Sebaceous gland produces
sebum
It:
● Protects skin from light and retain moisture
● Antibacterial properties, pro- and anti-inflammatory
● Involved in wound healing
Acne – Clinical Presentation
Open or close comedones
Nodules
Pustules
Papules
Open comedone
raised open follicle → black surface pigmentation (“black head”)
Closed comedone
raised blocked follicle (“white head”)
Nodule
disruption of follicular wall and release of
contents to surrounding dermis
Pustule:
papule with noticeable white or yellow centered
center (purulence)
Papule
closed, swollen, erythematous
Acne – Risk/Exacerbating Factors
● Chemicals ● Cosmetics ● Diet (breads, starches, sugar) ● Excoriation (picking, squeezing) ● Hormones (pregnancy, puberty) ● Hydration (humidity, sweating) ● Mechanical (hats, headbands, helmets) ● Medications ● Occupational ● Stress
Acne – Grading/Classification
Severity defined by the number and type of acne lesions
●Not standardized
Mild acne
Few erythematous papules and occasional pustules mixed with comedones
Moderate acne
Many erythematous papules and pustules and prominent scarring
Severe acne
Extensive pustules, erythematous papules, and multiple nodules in an inflamed background
Acne – Self-Treatment Pearls
Self-treatment is appropriate for mild acne only
• Address exacerbating factors – can be done before or in conjunction with treatment
• Treatment needs to be chronic, continuous, consistent -> adherence is important
• Set realistic goals: Symptoms likely to improve, but may not
resolve
Acne – Exclusions to Self-Care
Moderate to severe acne
● Pregnancy
● Suspected rosacea
Rosacea
- common skin condition that causes blushing or flushing and visible blood vessels in your face
- It may also produce small, pus-filled bumps
- These signs and symptoms may flare up for weeks to months and then go away for a while
Acne – Non-Pharmacologic Therapy
● Avoid abrasive scrubs/brushes ○ May worsen acne ● Cleanse skin twice daily ○ Mild soap or cleanser ● Dietary changes? ● Hydration ● Limit/eliminate exacerbating factors ● Physical therapies – glue-based strips, light therapy ○ Evidence? ○ Considered adjunct to pharmacologic therapy
Acne – Pharmacologic Therapy
Topical therapy is the standard of care ● Several OTC options • Adapalene • Benzoyl peroxide • Hydroxy acids (AHA, BHA) • Sulfur +/- resorcinol
Adapalene Brand Name
Differin
Adapalene MOA
- Anti-inflammatory; comedolytic; keratolytic
- Affects lesions not yet visible on the skin.
Adapalene OTC
0.1% gel
Adapalene Dosing
Apply daily at bedtime.
Adapalene Adverse Effects
allergic dermatitis; dry skin; skin irritation
*Tend to improve after the first month of therapy
Adapalene Patient Education
Avoid prolonged sun exposure/use sunscreen.
Full therapeutic effect takes 8-12 weeks.
Benzoyl Peroxide Brand Name
Acne Medication®; AcneFree®; BPO®; PanOxyl®; etc
Benzoyl Peroxide MOA
Antibacterial; comedolytic; keratolytic
Benzoyl Peroxide OTC Products
2.5-10% (higher strengths available as Rx)
Creams, gels, washes
Benzoyl Peroxide Dosing
Initiate 2.5% with 1-2 applications daily.
Increase frequency/strength every 1-2 weeks.
May increase until a mild peeling occurs.
Benzoyl Peroxide Adverse effects
Allergic contact dermatitis/anaphylaxis; bleaching; photosensitivity;
skin irritation*
*Tend to improve after the first month of therapy
Benzoyl Peroxide Patient Education
Avoid contact with clothes or hair – product has bleaching effects.
Avoid prolonged sun exposure/use sunscreen.
Full therapeutic effect takes 4-6 weeks.
Hydroxy Acids - AHAs Types
Alpha hydroxy acids (AHAs): citric, glycolic, and lactic acids
Hydroxy Acids - AHAs MOA
Keratolytic (assist in skin turnover/exfoliation)
Hydroxy Acids - AHAs OTC Products
4-10% (higher strengths available through dermatologists)
Hydroxy Acids - AHAs Adverse Effects
irritation; stinging
Hydroxy Acids - BHAs Types
Beta hydroxy acids (BHAs): salicylic acid
Hydroxy Acids - BHAs MOA
Comedolytic; keratolytic
Hydroxy Acids - BHAs OTC Products
0.5-2% (higher strengths available as Rx)
Gels, washes
Hydroxy Acids - BHAs Dosing
Gel: 1-2 times per day to affected area
Wash: 1-3 times per day
May increase until a mild peeling occurs
Hydroxy Acids - BHAs Adverse effects
Dryness; peeling
Toxicity: dizziness; hyperpnea; loss of hearing; nausea; tinnitus;
vomiting
Hydroxy Acids - BHAs Patient Education
Avoid excessive use.
Drug interactions – anticoagulants, NSAIDs, etc.
Full therapeutic effect takes 4-6 weeks.
Limit use to affected area.
Sulfur ± Resorcinol
Sulfur: precipitated or colloidal
Resorcinol: enhances effect of sulfur; not effective as monotherapy
Sulfur ± Resorcinol MOA
Antibacterial; keratolytic
Sulfur ± Resorcinol OTC Products
3-8% ± 2-3%
Creams, gels, lotions
Sulfur ± Resorcinol Dosing
1-3 times per day
Sulfur ± Resorcinol Adverse effects
Chalky yellow color; unpleasant odor
Avoid with allergy to sulfa drugs
Sulfur ± Resorcinol Patient Education
Not generally recommended for long-term use.
Creams/lotions as acne formulations
Less irritating/less effective – sensitive skin
Gels as acne formulations
Longest contact time – generally most effective
• Drying effects
Ointments as acne formulations
Occlusive – not used, worsen acne
Soaps/cleansers as acne formulations
Short contact time – little value
Acne – Product Selection
Product selection is based on individual patient needs,
skin type and acne severity
● “start low go slow”
Acne Product efficacy
Adapalene and benzoyl peroxide have similar efficacy
• Benzoyl peroxide: efficacy low concentration = efficacy high concentration
• Salicylic acid: less effective than benzoyl peroxide or adapalene
• Sulfur: adjunct therapy
Acne Patient education
Avoid eyes, mouth, open skin (cuts/scrapes).
• Do not combine with other products (unless instructed)
Improvement of acne
Complete resolution is unlikely
○ Decrease in number and severity of lesions is realistic
○ No improvement in 6 weeks → REFER
Continuation
Once symptoms have improved, continue treatment for
prevention
○ May decrease dose/frequency as tolerated
UVC Rays
- are short and don’t penetrate the ozone layer
UVB rays
- are longer and reach the skin, causing burning, tanning and signs of aging
UVA rays
- are the longest, they penetrate deep into the skin and cause the release of free radicals, as well as DNA changes that can result in skin cancer
Ultraviolet Radiation
Includes UVA and UVB rays
• Clouds only filter out 10-30%
• White or light colored surfaces reflect UVR
• Water reflects no more than 5% UVR (so you can burn
while under water…)
• Is cumulative
UVA
Majority of UVR
• Penetrates more deeply than UVB (dermis vs. epidermis)
• Less potent than UVB
• Immune system suppression and DNA damage
• Contributes to photoaging and skin cancer
• Primarily responsible for drug-induced photosensitivity
reactions
• Can penetrate window glass
UVB
1000x more potent than UVA • Highest intensity from 10am to 4pm • Primary cause of skin cancer • Needed for vitamin D production • Increases with increasing altitude • Does not penetrate window glass
Suntan/Sunburn
Degree depends on • Type and amount of radiation • Thickness of skin layers • Skin pigmentation • Skin hydration • Distribution and concentration of peripheral blood vessels
Suntan MOA
UVR → stimulates melanocytes → melanin generation and
oxidation
Suntan Clinical presentation
Immediate/prolonged darkening of the skin
-Does not offer “protection
Sunburn MOA
UVR → DNA damage → injury → inflammation + RBC leak
Sunburn Clinical Presentation
Superficial (partial-thickness) burn • Mild erythema, tenderness, pain, edema • Severe (full-thickness) burn • Development of vesicles • Fever, chills, shock
Sunburn Management
Symptomatic/supportive care
• Skin protectants – cocoa butter, petrolatum, aloe
• Systemic analgesics
• Topical anesthetics – benzocaine, dibucaine, lidocaine, tetracaine
Photoaging
Characterized by a breakdown of
elastin
Photoaging Risk Factors
Chemical exposure • Clinical and histologic changes • Smoking • UVR exposure • Wind exposure
Photoaging Clincal Presentation
May present as changes in skin color, surface texture, and functional capacity • May include development of pre and cancerous lesions
Skin Cancer
- Non-melanoma skin cancers (NMSCs)
- Melanoma
Non-melanoma skin cancers (NMSCs)
Basal cell carcinoma
• Squamous cell carcinoma
Melanoma
Arises from normal skin or mole
Skin Cancer – Melanoma Assessment
ABCDE rule for the ealry detection of melanoma
A- asymmetry
B- Borders ( the outer edges)
C- Color ( dark black or have multiple colors)
D- greater than 6 mm)
E- Evolving ( change in size, shape and color)
Sunburn & Photoaging Risk Factors
Fair skin • Blonde or red hair • Blue, green, or gray eyes • History of freckling • History of ≥1 serious/blistering sunburn(s) • Family history of melanoma • Immunosuppressant use • History of autoimmune disease • Excessive lifetime UVR exposure
Exclusions to Self-Care
● Allergy to all sun protectant ingredients
● <6 month of age
Non-Pharmacologic Treatments
Avoidance ■ Avoid tanning equipment ■ Minimize exposure during peak hours ■ Seek shade ○ Protective clothing ■ Hat ■ Long sleeves ■ SPF clothing
Pharmacologic Treatments
Sunscreen
Prevention – Sunscreen Properties
“Broad spectrum”
Sun protection factor (SPF)
■ Increased SPF = increased protection
● SPF 15 blocks 93% UVB filtered
● SPF 30 blocks 96.7% UVB filtered
● MAX = SPF 50+
Water-resistant
■ Cream-based > alcohol-based
■ Duration listed on label
Prevention – Sunscreen Types Chemical
Absorb UVR
● Products combined to maximize
UVA/UVB absorption
Prevention: Sunscreen Types Chemical Examples
● Aminobenzoic acid and derivatives ● Anthranilates ● Benzophenones ● Cinnamates ● Dibenzoylmethane derivatives ● Salicylates
Prevention: Sunscreen Types Physical
Reflect/scatter UVR
Prevention: Sunscreen Types Physical Examples
Titanium dioxide
● Zinc oxide
Prevention – Sunscreen Application
Apply 15-30 minutes before exposure
• Reapply every 2 hours, or after 40-60 minutes of swimming or
sweating or after toweling off
• For sufficient protection, the average adult in a bathing suit should
apply 9 portions of sunscreen (approximately ½ teaspoon each)
• Face/neck = ½ teaspoon
• Arms/shoulder = ½ teaspoon per side
• Torso = ½ teaspoon front/back
• Legs/feet = 1 teaspoon per side
