Sec 36 Topical Therapy and Sec 38 Physical Treatments Flashcards by Charlene DPA

The rate-limiting barrier to percutaneous drug delivery.

Stratum corneum

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This cornified layer is composed of ceramides, free fatty acids, and cholesterol in a 1:1:1 molar ratio

Stratum corneum

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Composition: Stratum corneum

50% ceramides (acylceramides being the most abundant)
35% cholesterol
15% free fatty acids

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Two main routes for permeation through the stratum corneum

Transepidermal pathway

2. Transappendageal pathway

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Involves the flow of molecules through the eccrine glands and hair follicles via the associated sebaceous glands

Transappendageal, or shunt route

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Molecules pass between the corneocytes via the intercellular micropathway, or through the cytoplasm of dead keratinocytes and intercellular lipids

Transepidermal route

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Considered the most important route for cutaneous drug delivery

Intercellular pathway

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Difference in penetration (from most to least penetration)

Mucous membrane
Scrotum
Eyelids
face
chest and back
Upper arms and legs
lower arms and legs
Dorsa of hands and feet
Palmar and plantar skin
Nails

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Occlusion increases drug delivery by

10-100x

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Associated with adherence to a treatment regimen

Female gender
Employment
Being married
Low prescription costs

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Decrease in drug response when used over a prolonged period of time

Tachyphylaxis

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Worsening of preexisting dermatoses

Rebound effect

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Emulsifying agents

Cholesterol
Disodium mono-oleamidosulfosuccinate 
Emulsifying wax
Polyoxyl 40 stearate
Polysorbates
Sodium laureth sulfate
Sodium lauryl sulfate

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Auxiliary emulsifying agents/emulsion stabilizers

Carbomer
Catearyl alcohol
Cetyl alcohol
Glyceryl monostearate
Lanolin and lanolin derivatives 
Polyethylene glycol
Stearyl alcohol

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Stabilizers

Benzyl alcohol
Butylated hydroxyanisole 
Butylated hydroxytoluene chlorocresol
Citric acid
Edetate disodium
Glycerin
Parabens
Propyl gallate
Propylene glycol
Sodium bisul te
Sorbic acid/potassium sorbate

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Solvents

Alcohol
Diisopropyl adipate glycerin 
1,2,6-Hexanetriol 
Isopropyl myristate 
Propylene carbonate 
Propylene glycol 
Water

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Thickening agents

Beeswax
Carbomer 
Petrolatum 
Polyethylene 
Xanthan gum

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Emollients

Caprylic/capric triglycerides cetyl alcohol
Glycerin
Isopropyl myristate
Isopropyl palmitate
Lanolin and lanolin derivatives 
Mineral oil
Petrolatum
Squalene
Stearic acid
Stearyl alcohol

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Humectants

Glycerin
Propylene glycol
Sorbitol solution

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Absorb moisture and decrease friction; adhere poorly to the skin; use is mainly limited to cosmetic and hygienic purposes; used in the intertriginous areas and on the feet

Powders

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Also referred to as a cataplasm; a wet solid mass of particles, sometimes heated; used as wound cleansers and absorptive agents in exudative lesions such as decubiti and leg ulcers

Poultice

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Semisolid preparations that spread easily; petrolatum-based vehicles, capable of providing occlusion, hydration, and lubrication

Ointments

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Also called oleaginous bases; often referred to as emollients because they prevent the evaporation of moisture from the skin; composed of a mixture of hydrocarbons of varying molecular weights; greasy and can stain clothing

Hydrocarbon bases

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Contain hydrophilic substances that allow for the absorption of water-soluble drugs; these are lubricating and hydrophilic, and they can form emulsions; greasy to apply; do not contain water; examples: anhydrous lanolin and hydrophilic petrolatum

Absorption bases

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Contains <25% water, with oil being the dispersion medium with the two phases separate unless shaken; less greasy, spread easily on the skin, and provide a protective film of oil that remains on the skin as an emollient, while the slow evaporation of the water phase provides a cooling effect

Water-in-oil emulsion

Contains >31% water with the aqueous phase may comprise up to 80% of the formulation; one most commonly chosen to deliver a dermatologic drug; spread very easily, are water washable and less greasy, and are easily removed from the skin and clothing

Oil-in-water emulsion

Consist either primarily or completely of various PEGs; water soluble, will not decompose, and will not support the growth of mold, and therefore require no preservative additives; much less occlusive than water-in-oil emulsions, nonstaining, greaseless, and easily washed off of the skin

Water-soluble bases

Made from water-soluble bases by formulating water, propylene glycol, and/or PEGs with a cellulose derivative or carbopol; consists of organic macromolecules uniformly distributed in a lattice throughout the liquid; suitable for facial or hairy areas

Gels

Incorporation of high concentrations of powders (up to 50%) into an ointment such as a hydrocarbon base or a water-in-oil emulsion; function to localize the effect of a drug that may be staining or irritating; also function as impermeable barriers that serve as protectants or sunblocks; less greasy than ointments, more drying, and less occlusive

Pastes

Involves the dissolution of two or more substances into homogenous clarity. The liquid vehicle may be aqueous, hydroalcoholic, or nonaqueous

Solutions

A hydroalcoholic solution with a concentration of alcohol of approximately 50%

Tincture

A nonaqueous solution of pyroxylin in a mixture with ether and ethanol, and is applied to the skin with a soft brush

Collodion

Nonaqueous solutions of drugs in oil or alcoholic solutions of soap; can be used as counterirritants, astringents, antipruritics, emollients, and analgesics

Liniments

Two-phase system consisting of a finely divided, insoluble drug dispersed into a liquid in a concentration of up to 20%; easier to apply and allow for uniform coating of the affected area; more drying than ointments, and preparations with alcohol tend to sting eczematized or abraded skin

Suspension or lotion

Lotions to which a powder is added to increase the surface area of evaporation; effectively dries and cools wet and weeping skin; tend to sediment

Shake lotions

Triphasic liquids composed of oil, organic solvents and water, which are kept under pressure in aluminum cans; formulated with a hydrocarbon propellant

Foams

Involve formulating the drug in a solution within a pure propellant which is a blend of nonpolar hydrocarbons; allow for the ease of application and high patient satisfaction but expensive and potentially ecologically damaging

Aerosols

Compound that is able to promote drug transport through the skin barrier

Penetration enhancer

Application of crystals (generally aluminum oxide) on the skin and the collection of such crystals and skin debris under vacuum suction

Microdermabrasion

Nontherapeutic ingredients and include the preservatives, antioxidants, and chelating agents

Stabilizers

Increase the viscosity of products or suspend ingredients in a formulation

Thickeners

Patients may detect burning or stinging sensations without any signs of cutaneous irritation after applying a topical medication

Sensory irritant contact dermatitis

Reported with the long-term use of nitrogen mustard

Keratoacanthomas Basal and squamous cell carcinomas Lentigo maligna Primary melanoma

Factors that modulate absorption also influence toxicity

``` Concentration of the drug Vehicle Use of occlusion Body site and area treated Frequency of use Duration of therapy Nature of the diseased skin ```

Parameters that Affect Drug Amounts in Skin Compartments

1. Formulations may undergo drastic changes in composition and structure 2. Drug or formulation may affect the skin barrier, resulting in time-dependent changes of the barrier function 3. Skin barrier may be affected by the type and progression of a disease 4. Regional variations in the barrier properties of the skin 5. Skin may respond to topical drug, enhancing or retarding percutaneous absorption 6. Metabolic capacity of skin may lead to exposure of skin or systemically to both parent drug and pharmacologically active metabolite(s)

Highly responsive dermatoses to topical application of corticosteroids

Psoriasis (intertriginous) Atopic dermatitis (children) Seborrheic dermatitis Intertrigo

Moderately responsive dermatoses to topical application of corticosteroids

``` Psoriasis Atopic dermatitis (adults) Nummular eczema Primary irritant dermatitis Papular urticaria Parapsoriasis Lichen simplex chronicus ```

Least responsive dermatoses to topical application of corticosteroids

``` Palmoplantar psoriasis Psoriasis of nails Dyshidrotic eczema Lupus erythematosus Pemphigus Lichen planus Granuloma annulare Necrobiosis lipoidica diabeticorum Sarcoidosis Allergic contact dermatitis, acute phase Insect bites ```

The amount of an active ingredient that is still in contact with the nonvolatile constituents of its formulation after the latter had been massaged into the skin surface

Reservior

Microscopic spheres comprising a bilayer that encloses an inner aqueous core

Liposomes

Potential sites of discontinuity in the integrity of the skin barrier

Appendages

The uptake of compounds by the cutaneous microvasculature; directly related to the surface area of the exchanging capillaries as well as their blood flow

Resorption

MOA: Blockage of DNA synthesis by inhibition of thymidylate synthetase

5-fluorouracil

MOA: Alkylating activity, immune stimulation

Mechlorethamine (nitrogen mustard)

MOA: Alkylation agent: inhibits DNA, RNA, and protein synthesis

Carmustine

MOA: Antimitotic agent: acts by disrupting microtubules, blocking cell division in metaphase

Vinblastine

MOA: Disrupts DNA synthesis and causes scission of DnA strands

Bleomycin

MOA: Antimetabolite: interferes with DNA synthesis (inhibition of dihydrofolate reductase)

Methotrexate

MOA: Binds tubulin, disrupting the cellular cytoskeleton

Podophyllin

MOA: Cytotoxic - promotes phospholipid turnover | and modulates membrane signal transduction by inhibition of protein kinase c

Miltefosine

Indications: 5-fluorouracil

Actinic keratoses | Superficial basal cell carcinomas

Indications: Mechlorethamine (nitrogen mustard)

Mycosis fungoides Stages IA, IB

Indications: Carmustine

Mycosis fungoides Stages IA, IB

Indications: Vinblastine

Kaposi sarcoma

Indications: Bleomycin

Viral warts Hemangiomas Keloids Hypertrophic scars

Indications: Methotrexate

Keratoacanthoma

Indications: Podophyllin

Anogenital warts | Facial angiofibromas

Indications: Miltefosine

Cutaneous metastases of breast cancer Cutaneous lymphomas Cutaneous mastocytosis

Indications: Tacrolimus and Pimecrolimus

Second-line therapy for atopic dermatitis Children older than 2 years Adults Short-term, noncontinuous chronic therapy

Indications: Imiquimod

``` External anogenital warts Actinic keratosis Superficial BCC smaller than 2 cm on trunk, neck, extremities Immunocompetent adults When surgical options less appropriate Biopsy confirmed ```

Contraindications: Tacrolimus and Pimecrolimus

Immunocompromised Netherton syndrome Active bacterial or viral infection Phototherapy

Contraindications: Imiquimod

Immunocompromised | Refractory, thicker, actinic keratoses

Dosing of Imiquimod for Anogenital warts

3x/week | Max: 16 weeks

Dosing of Imiquimod for Actinic keratosis

2x/week for 16 weeks

Dosing of Imiquimod for Superficial BCC

5/week for 6 weeks

Complications: Tacrolimus and Pimecrolimus

Elevated blood levels and risk of systemic immuno- suppression Unclear long-term risk of lymphoproliferative disease Unclear long-term malignancy risk Eczema herpeticum

Complications: Imiquimod

Irritant contact dermatitis Ulceration Incomplete treatment of malignancy

Bisbiguanide which (1) binds to negatively charged bacterial cell wall and cytoplasmic components leading to altered osmotic equilibrium and (2) precipitation of cytoplasmic components; for gram-positive, gram- negative bacteria, enveloped viruses, and fungi; can cause keratitis, ototoxicity; used for antiseptic surgical hand B scrub and surgical site preparation

Chlorhexidine

Dye with unknown MOA; for some vegetative gram- positive bacteria and yeast; can cause potential skin necrosis at high concentrations or when occluded, stains skin and clothing, tattooing when applied over granulation tissue and mutagenic; used for impetiginized eczema, mycotic skin infections, oral candidiasis and superficial skin infections

Gentian violet

Dye with unknown MOA; for some vegetative gram- positive bacteria and yeast; can cause potential skin necrosis and stains skin and clothing; used for impetiginized eczema, mycotic skin infections, oral candidiasis and superficial skin infections

Brilliant green

Peroxide which oxidizes microbial molecules and is a broad spectrum antimicrobial; can cause bleaching of hair; used for cleansing of wounds, suppurating ulcers, and local infections

Hydrogen peroxide

Iodophor which oxidizes and releases of free iodine; for gram-positive, gram-negative, enveloped viruses, fungi, sporicidal, Mycobacterium tuberculosis; can cause potential systemic toxicity in neonates or when applied to large body surface area, neutralized by blood, serum proteins, and sputum; used as antiseptic surgical hand c scrub, prevention or treatment of topical site infection associated with surgery, burns, minor cuts/ scrapes

Povidone-iodine

Iodophor which oxidizes and releases free iodine, chelates bacterial surface and trace metals needed for bacterial growth; for gram-positive, gram-negative, enveloped viruses, fungi, sporicidal, M. tuberculosis; may have possible irreversible optic atrophy and peripheral neuropathy (oral), contraindicated in children <2 years of age, contraindicated for diaper rash, stains skin yellow and neutralized by blood, serum proteins, and sputum; approved for fungal — infections; also used for pyoderma, folliculitis, and impetigo

Clioquinol

Imidazole which acts by creation of reduced intermediate compounds and free radicals on anaerobes, protozoa, and microaerophilic bacteria used in Rosacea; contraindicated during 1st trimester of pregnancy

Metronidazole

A fermentation product of Pseudomonas fluorescens which acts by inhibiting bacterial isoleucyl-t- RnA synthetase on gram-positive, some gram-negative, but spares normal flora; used in non-bullous impetigo, B eradication of nasal carriage of S. aureus; potentially toxic amounts of polyethylene glycol contained in vehicle may be absorbed in patients with extensive burns or open wounds

Mupirocin

Pleuromatilin which acts by inhibits 50S subunit of prokaryotic ribosome on Gram + bacteria; used in nonbullous impetigo

Retapamulin

Dicarboxylic acid which acts by inhibition of microbial respiratory chain of Propionibacterium acnes and S. epdermidis; used in Acne; may cause hypo pigmentation

Azaleic acid

Peroxide which oxidizes microbial molecules; used in Acne; bleaches dark clothing

Benzoyl peroxide

Astringent which acts by coagulation of proteins used for weeping, impetiginized skin disorders; should not be used under impervious material to prevent evaporation

Aluminum salts

Astringent which acts by oxidation microbial molecules used for weeping, impetiginized skin disorders; can cause skin discoloration and caustic at high concentrations or with contact of undissolved crystals

Potassium permanganate

Astringent which acts by precipitation of bacterial proteins by free silver ions used for eeping, impetiginized skin disorders, cauterization of wounds, removal of granulation tissue and aseptic prophylaxis of burns; can cause black skin discoloration, caustic at high concentrations and potential methemoglobinemia

Silver nitrate

Agents that cause contraction of the tissues, arrest of secretion, or control of bleeding or a drug product that is applied to the skin or mucous membranes for a local and limited protein coagulant effect

Astringent

Synthetic pyrethroid which inhibits nerve cell sodium ion influx used in lice and scabies and used on clothing as an insect repellant; may cause itching and stinging on application and contraindicated for infants <2 months of age

Permethrin (1% or 5%)

Natural botanical which inhibit nerve cell sodium ion influx or inhibits cytochrome P450; used for lice; can cause itching and stinging on application and ragweed or chrysanthemum allergy

Synergized pyrethrins

Organophosphate which is a cholinesterase inhibitor used in lice; flammable; not approved for children <6 years of age

Malathion (0.5%)

Crotonyl-N-ethyl- O-toluidine with unknown MOA; used in Scabies

Crotamiton (10%)

Organochlorine which is a cholinesterase inhibitor used in lice and scabies; may cause seizures, muscle spasms, aplastic anemia; not for use in children <3 years, pregnant or breastfeeding women, patients with underlying neurologic disorders, or over broken skin

Lindane (1%)

Fermentation product which acts by generalized central nervous system excitation leading to paralysis in lice

Spinosad (0.9%)

Topical antipruritic has local anesthesia and histamine antagonism

Diphenhydramine

Tricyclic antidepressant with antipruritic effects through histamine antagonism, interference with neuronal synaptic communication; decreased awareness through production of drowsiness

Doxepin

Cyclic terpene alcohol which acts as a counter-irritant; cooling sensation may be the result of a direct interaction of menthol with cold receptors and/or nerve fiber

Menthol

In low concentrations (0.5% to 2.0%) acts as an antipruritic agent through its anesthetic effect; percutaneously absorbed and should be avoided in pregnant women and infants. In higher concentrations, it is caustic and is used for deep chemical peels

Phenol

Effective in cases of mild to moderate pruritus; inhibits conduction of nerve impulses by altering the cell membrane permeability to ions; onset of action: 2-5 minutes

Pramoxine Hydrochloride

A vitamin D analog which inhibits epidermal proliferation, induces epidermal differentiation, and exerts anti-inflammatory effects

Calcipotriol

Keratolytic (available at concentrations up to 12%); increases ceramide production by keratinocytes improving water barrier function

Lactic acid

Humectant that is proteolytic at high concentrations; added to some topical glucocorticoid preparations to increase penetration; used for dry skin and nail plate destruction

Urea

In concentrations of 3% to 6%, it causes shedding of scales by softening the stratum corneum, dissolving the intracellular matrix, and loosening connections between corneocytes. In concentrations > 6%, it is destructive to tissue.

Salicylic acid

Humectant, occlusive, and keratolytic agent, often combined with other medications to enhance their penetration used in patients with lamellar ichthyosis and n various other hyperkeratotic diseases

Propylene glycol

Reduce the thickness of hyperkeratotic stratum corneum by an incompletely understood mechanism wherein the acids may directly solubilize the protein components of desmosomes or activate endogenous hydrolytic enzymes by changing the pH of the stratum corneum, resulting in keratolysis

A-Hydroxy acids

UVB filter most commonly used PABA derivative and is photounstable

Padimate O

Cinnamate most widely used UVB filter and is photounstable; rarely a photoallergen

Octinoxate

Weak UVB absorbers which improves photostability of other filters

Octisalate

Weak UVB absorbers. good substantivity: used in water-resistant sunscreens and hair-care products

Trolamine salicylate

Photostable UVB filter and improves photostability of photolabile filters

Octocrylene

Water soluble UVB filter and enhances sun protection factor of the final product

Ensulizole

Most commonly used UVA filter; most common cause of photoallergic contact dermatitis to UV filters

Oxybenzone

A weak UVA filter with no sensitization reaction reported.

Meradimate

Photounstable UVA1 filter which enhances the photodegradation of octinoxate

Avobenzone

Factors affecting sun protection of garments

``` Style of garment Number of layers Fabric thickness Type of fibers (polyester > wool, silk, nylon > cotton, rayon) Stretching Laundering Wetness Chemical treatments ```

Ratio of the minimal erythema dose (MED) of a subject's sunscreen-protected skin over the MED of the unprotected skin

Sun protection factor (SPF)

Most widely used method to evaluate protection against UVA

Persistent pigment darkening (PPD)

Quantifies the ability of the sunscreen to prevent immunosuppression

Immune Protection Factor (IPF)

Narrowband UVB by MED

``` 1-cm2 areas on the lower back or inner aspect of the forearm: 200, 400, 600, 800, 1,000, 1,200 mJ/cm2 read at 24 h initial: 50-70% of MED 2–5 times per week Increase by 10%–20% ```

Narrowband UVB by Fitzpatrick Skin Phototype

``` I - 130 - 2,000 II - 220 - 2,000 III - 260 - 3,000 IV - 330 - 3,000 V - 350 - 5,000 VI - 400 - 5,000 ```

Broadband UVB by MED

1-cm2 areas on the lower back or inner aspect of the forearm: 20, 40, 60, 80, 100, 120 mJ/cm2 read at 24 h initial: 50-70% of MED 2–5 times per week Increase by 25% x 10 treatments then 10% thereafter

Broadband UVB by Fitzpatrick Skin Phototype

``` I - 20 II - 25 III - 30 IV - 40 V - 50 VI - 60 ```

Oral PUVA by MPD

1-cm2 areas on the lower back or inner aspect of the forearm: 0.5, 1.0, 2.0, 3.0, 4.0, 5.0 mJ/cm2 UVA read 72 h after UVA initial: 50-70% of MPD 2-4 times per week Increase UVA dose per table entries each week

Oral Psoralen dose

8-MOP micronized 0.6 mg/kg; 120 minutes before UVA 8-MOP dissolved 0.4-0.6 mg/kg; 90 minutes before UVA

Oral PUVA by Fitzpatrick Skin Phototype

``` I - 0.5 - 0.5 II - 1.0 - 0.5 III - 1.5 - 1.0 IV - 2.0 - 1.0 V - 2.5 - 1.5 VI - 3.0 - 1.5 ```

Bath Psoralan dose

8-MOP dissolved in bath water for a final concentration of 1.0 mg/l Bath water is at body temperature (98.6°F) Duration of bath is 15–20 minutes

Modification of Phototherapy Dose: No erythema

Increase by 25%

Modification of Phototherapy Dose: Erythema with no pain

No increase

Modification of Phototherapy Dose: Erythema with pain

Hold treatment until symptoms subside

Modification of Phototherapy Dose: Erythema with pain and blistering

Hold treatment until symptoms subside and then reduce dose by 50% from last dose

Modification of Phototherapy Dose: Missed <1 week

No increase in dose

Modification of Phototherapy Dose: Missed 1–2 weeks

Decrease dose by 50% (BB-UVB) or 25% (NB-UVB or PUVA)

Modification of Phototherapy Dose: Missed 2–3 weeks

Decrease dose by 75% (BB-UVB) or 50% (NB-UVB PUVA)

Modification of Phototherapy Dose: Missed >3 weeks

Restart at initial exposure dose

Diseases amenable to UVA1

``` Atopic dermatitis Cutaneous T-cell lymphoma Localized and systemic scleroderma Chronic GVHD Lymphomatoid Papulosis Telangiectasis macularis eruptiva Perstans Urticaria pigmentosa Granuloma annulare Chronic hand eczema ```

Phototherapy-Responsive Diseases for therapy

``` Psoriasis Palmoplantar pustulosis Mycosis fungoides (stages IA, IB) Vitiligo Atopic dermatitis Generalized lichen planus Urticaria pigmentosa Cutaneous graft-versus-host disease Generalized granuloma annulare Pityriasis lichenoides Lymphomatoid papulosis Pityriasis rubra pilaris Localized scleroderma ```

Phototherapy-Responsive Diseases for prevention

``` Polymorphous light eruption Hydroa vacciniformea Solar urticaria Erythropoietic protoporphyria Chronic actinic dermatitis ```

Indications for Photopheresis (with sufficient evidence)

Erythrodermic cutaneous T-cell lymphoma Chronic graft-versus-host disease Acute graft-versus-host disease Organ transplant rejection

Indications for Photodynamic Therapy - Oncologic

Actinic keratosis Bowen disease Superficial BCC ``` Off label: Actinic Cheilitis Nevoid BCC syndrome Keratoacanthoma Superficial SCC Kaposi sarcoma Cutaneous metastases Cutaneous T-cell lymphoma ```

``` 308 nm Excited dimer molecules (Xe-Cl) Different gases Gas Pulsed μs–ms ```

Excimer laser

``` 532 nm Nd Crystal: Yttrium- aluminum Garnet (Y3Al5O12) Solid state Pulsed μs–ms ```

“KTP” laser (Nd:YAG laser) frequency doubled with KTP crystal

``` 585–600 nm Dyes (e.g., Rhodamines) Organic solvents Liquid Pulsed ms ```

Dye laser

``` 694 nm Cr Al2O3 Solid state Pulsed μs–ms ```

Ruby laser

``` 755 nm Cr Chrysoberyl (BeAl2O4) Solid state Pulsed μs–ms ```

Alexandrite laser

``` Different wavelengths (e.g. 810, 940) InGaAs, AlGaAs Semiconductor material Solid state Pulsed μs–ms ```

Diode laser

``` 1,064 nm Nd Crystal: Yttrium-aluminum Garnet (Y3Al5O12) Solid state Cw, Pulsed μs–ms ```

Nd:YAG laser

``` 2,940 nm Er Crystal: Yttrium-aluminum Garnet (Y3Al5O12) Solid state Pulsed ms ```

Er:YAG laser

``` 10,600 nm CO2 Different gases Gas Cw, Pulsed ms ```

CO2 laser

Power × Time | W x s

Energy (J)

Power / Area | W / cm2

Intensity

Power x Time / Area

Radiant exposure (“Fluence”)

Target - DNA, proteins Effect - Photochemical reactions Application - Comparable to narrow band UVB 311nm

Excimer (XeCl) (308)

Target - Vascular lesions; Tissue Effect - Semiselective coagulation; Coagulation Application - Telangiectases, spider nevi, venous lakes; Syringoma, xanthelasma, epidermal nevi

Argon (488/514)

Target - Vascular lesion Effect - Selective coagulation (“KTP” laser) Application - Telangiectases, spider nevi, venous lakes

Frequency-doubled Nd:YAG (532)

Target - Pigmented lesions Effect - Selective and fast heating Nd:YAG (explosion) Application - Benign melanin-containing lesions, tattoos (red)

Frequency-doubled Nd:YAG (532)

Target - Vascular lesions; Tissue Effect - Selective Coagulation Application - PWS, telangiectases, rosacea, spider nevi; Scars, keloids, warts, photoaging

Flashlamp pulsed dye (585–600)

Target - Pigmented lesions Effect - Selective and fast heating (explosion) Application - Benign melanin-containing lesions, tattoos (black, blue, green)

Ruby (694)

Target - Vascular lesions; Tissue; Pigmented lesions Effect - Selective coagulation; Selective and fast heating (explosion) Application - large vessels (leg veins, hypertrophic PWS) Hair removal; Benign melanin-containing lesions, tattoos (black, blue, green)

Alexandrite (755)

Target - Vascular lesions; Tissue Effect - Selective coagulation Application - large vessels (leg veins, hypertrophic PWS); Hair removal

Diode (810)

Target - Vascular lesions, Tissue, Pigmented lesions Effect - Unspecific coagulation, Selective coagulation, Selective and fast heating (explosion) Application - Vascular malformations, tumors; Large vessels (leg veins, hypertrophic PWS), Hair removal; Benign melanin-containing lesions, tattoos (black, blue, green)

Nd:YAG (1,064)

Target - Tissue Effect - Selective coagulation (nonablative) Application - Skin remodeling, photoaging

Diode (1,450)

Target - Tissue Effect - Selective and fast heating (ablation) Application - Skin resurfacing, epidermal ablation

Er:YAG (2,960)

Target - Tissue Effect - Unspecific coagulation (vaporization); Selective and fast heating (ablation) Application - Vaporization of tissue; Skin resurfacing, epidermal ablation

CO2 (10,600)

Refers to the delivery of specified radiation dose in temporally separate treatments

Fractionation

A phenomenon describing a cutaneous reaction in the area of previous radiation exposure, in response to specific systemic agents

Radiation recall

Faint erythema | Dry desquamation

Radiation Dermatitis Grade 1

Moderate-to-brisk erythema Patchy moist dequamation (mostly confined to skin folds and creases) Moderate edema

Radiation Dermatitis Grade 2

Moist desquamation (other than skin folds and creases) Bleeding induced by minor trauma or abrasion

Radiation Dermatitis Grade 3

Skin necrosis Ulceration of full thickness of dermis Spontaneous bleeding

Radiation Dermatitis Grade 4

Death

Radiation Dermatitis Grade 5

Delivers 20% less energy to melanin and proportionally more to oxyhemoglobin thus, reducing the epidermal damage, especially for dark skin. The epidermis is further protected by cooling during the procedure. The spot size can be varied from 5–12.5 mm and makes possible the rapid treatment of larger areas.

Alexandrite Laser (755 nm)

At this wavelength, the energy is well absorbed in the follicle but less absorbed by competing chromophores like oxyhemoglobin or water. In addition, a penetration depth of 3 mm can be reached. The laser light is scarcely absorbed by the epidermis, making the device well suited to dark skin. The long impulse duration (up to 50 ms) and high fluences make epidermal cooling mandatory.

Diode Laser (800/810 nm)

This laser penetrates very deep (5-7 mm), so that even deep-lying follicles receive enough energy for epilation. There is also very little epidermis absorption, making the device well suited for dark skin. Surface cooling is essential to reduce pain and side effects. This has the fewest side effects but is most painful.

Pulsed Nd: YAG Laser (1,064 nm)

These sources have a broad emission spectrum extending into the near infrared region, which allows for excellent depth of penetration and have the largest spot sizes (around 5 cm2) of all the photoepilation units, which make rapid treatment possible. In the epilation mode, a cut-off filter at 600 nm is usually employed in order to filter out shorter wavelengths destined to be absorbed in the epidermis. The impulse durations are 0.5–25 ms, while 20 ms is usually chosen. A cooling gel is used to improve the coupling of light into the skin, cool the epidermis, and reduce pain. This is a method well suited for all skin types and with few complications.

High-energy Flashlamps (590–1,200 nm).