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THE USE OF LIGHT THERAPY IN
DERMATOLOGY
Dr Ash Chadha
Ultraviolet radiation
PhototherapyCertain types of electromagnetic radiation can be used to treat some skin disorders.
Blue light acne treatment UVB therapy Narrowband UVB therapy UVA1 therapy Targeted phototherapy
Home phototherapy Photochemotherapy (PUVA) lasers/IPL treatmentPhotodynamic therapy (PDT) including Metvix PDT for skin cancers
Blue light acne treatment
Blue light acne treatment is a non-invasive procedure that uses light in the blue wavelength range of 405-420 nm to kill the Propionobacterium acnes or P. acnes bacteria in skin. This photodynamic therapy is FDA-approved for the treatment of moderate acne vulgaris or acne vulgaris that has not responded to other acne therapies.
Clearlight acne treatment
How does it work?
The bacteria in acne release porphyrins. These are naturally occurring substances in the body, arising from the breakdown of haemoglobin in red blood cells.
When porphyrins absorb light of certain wavelengths, free radical damage is produced, and this destroys the bacteria.
Blue light acne treatment uses a narrow-band, high-intensity blue light source that is readily absorbed by porphyrins released by the bacteria causing acne.
What does the procedure involve?
Blue light acne treatment is administered via a blue light delivery system. The procedure simply involves a patient sitting in front of a blue light lamp for about 15 minutes. Generally 2 sessions per week over a 4-week period is all that is required.
Pre-treatment with ALA requires the topical application of ALA 30 minutes prior to sitting in front of the blue light lamp for about 8 minutes. Treatments are usually spaced at 2-week intervals. The number of treatments depends on the severity of acne and improvements seen.
Blue light delivery systems can be purchased and self-administered at home, a dermatologist should oversee its use.
How effective is it?
Several small studies have shown that blue light acne treatment appears to improve acne vulgaris with a reduction in inflammation and the number of pustules and papules in some individuals.
In one study, nodulocystic acne lesions worsened when treated with blue light.
Further large, controlled studies are needed to prove their efficacy and long-term effects. Other treatments for acne may be more suitable in the individual case.
UVB Phototherapy
UVB phototherapy refers to irradiation with short wave ultraviolet radiation. To treat the whole body, the patient, undressed, stands in a specially designed cabinet containing fluorescent light tubes. Traditionally, broadband UVB has been used, but increasingly, narrowband UVB phototherapy (311nm) is provided.
Phototherapy cabinet
Whole body unit
Increasing doses of UVB are given each exposure (three to five times weekly), aiming to turn the skin slightly pink. Sometimes uncomfortable sunburn will occur, at its worst about 8 hours after treatment. This fades over the next few days and should be treated with frequent and liberal emollients. The effect of UVB is similar to the sun. Excessive exposure contributes to aging skin and to the risk of skin cancer.
Whole body PUVA cabinets
Psoriasis is a common inherited skin disorder, which may vary considerably in extent and severity. Neither phototherapy nor any other available treatment effects a permanent cure. UVB is suitable for most people with extensive psoriasis. It may not suit those with very fair skin, or those whose psoriasis gets worse in sunlight. Initially most patients have their treatment three times a week. The first few exposures will be short (less than 5 minutes). The length of exposure is gradually increased, according to the patient's response, up to a maximum of 30 minutes per session. Few patients require such long exposures, most being controlled with shorter times. Most psoriasis patients will have their psoriasis cleared or much improved after 12 to 24 treatments. At this stage treatments will usually be discontinued. Even without treatment, the skin may remain clear for some months. However, the psoriasis may later flare up again, and further UVB treatment may be necessary. Those cases of psoriasis which appear to be resistant to UVB may still be helped by another form of ultraviolet treatment called PUVA, or other treatments (e.g. ointments or tablets).
Psoriasis
UVB is occasionally used for severe cases of dermatitis, especially atopic eczema. Frequency and dosage of treatment is similar to that used for psoriasis. However, a course of phototherapy may need to be more prolonged than that generally required for psoriasis.
Dermatitis
UVB is one of the most effective treatments for vitiligo. Treatments must be cautious as the white skin burns easily. It may take several months to see an improvement.
Vitiligo
Other skin conditions
Many other skin conditions have been effectively treated with UVB, including Generalised itch, Prurigo, Cutaneous T-cell lymphoma, Pityriasis lichenoides, and symptomatic dermographism.
Narrowband UVB phototherapy
Narrowband UVB is now the most common form of phototherapy used to treat skin diseases (2008). Narrow-band refers to a specific wavelength of ultraviolet (UV) radiation, 311 to 312 nm. UVB phototherapy was formerly provided as a broadband source (290 to 320 nm).
This range of UV radiation has proved to be the most beneficial component of natural sunlight for psoriasis. Narrowband UVB may also be used in the treatment of many other skin conditions including atopic eczema, vitiligo, pruritus, lichen planus, polymorphous light eruption, early cutaneous T-cell lymphoma and dermographism.
Compared with broadband UVB:
•Exposure times are shorter but of higher intensity. •The course of treatment is shorter. •It is more likely to clear the skin condition. •Longer periods of remission occur before it reappears.
What does the treatment involve?
Patients attend two to five times weekly. The patient is placed in a specially designed cabinet containing fluorescent light tubes. The patient stands in the centre of the cabinet, undressed except for underwear, and wears protective goggles. Usually the whole body is exposed to the UVB for a short time (seconds to minutes). The amount of UV is carefully monitored. A number of protocols exist depending on the individual's skin type, age, skin condition and other factors. The skin may remain pale or turn slightly pink (the Minimal Erythemal Dose) after each treatment. Patches of psoriasis generally start to become thinner after five to ten treatments. Most patients with psoriasis require 15 to 25 treatments to clear.
Side effectsNarrow-band UVB can result in burning, just like sunlight and broadband UVB. Frequent emollients should be applied to burned skin, and if recommended by the dermatologist/ nurse specialist, topical steroids. It sometimes provokes polymorphous light eruption. Long term exposure to ultraviolet radiation ultimately causes skin ageing and skin cancers. Although the risk from narrow-band UVB is unknown, research to date suggests it is no more risky than broadband UVB and probably less risky than photochemotherapy (PUVA).
PUVA (photochemotherapy)What is PUVA?
PUVA or photochemotherapy is a type of ultraviolet radiation treatment (phototherapy) used for severe skin diseases. PUVA is a combination treatment which consists of Psoralens (P) and then exposing the skin to UVA (long wave ultraviolet radiation). It has been available in its present form since 1976. Psoralens are compounds found in many plants which make the skin temporarily sensitive to UVA. The ancient Egyptians were the first to use psoralens for the treatment of skin diseases thousands of years ago. Medicine psoralens include methoxsalen (8-methoxypsoralen), 5-methoxypsoralen and trisoralen.
hole body PUVA cabinets
Whole body PUVA
For oral PUVA, methoxsalen capsules are taken two hours before the appointment for treatment. For bathwater PUVA, the patient soaks in a bath containing a solution of psoralens. In most cases, treatment is undertaken two or three times each week. During treatment, the patient usually stands in a cabinet containing 24 or more 6-foot long UVA fluorescent bulbs. The patient should always wear goggles to protect the eyes from exposure to the radiation. Usually, he or she is dressed only in body exposure. Sometimes just arms and legs may be exposed to the radiation, in which case the patient should wear the same clothing each treatment to prevent inadvertently exposing a new area of skin. The UVA lamps stay on for increasing lengths of time, starting with about one minute and extending for up to half an hour. Their may be fans and/or air conditioning to cool the cabinet, as it tends to get very warm with more prolonged treatment times.
Localised PUVAThose patients requiring treatment to small areas only may be treated using a smaller hand and foot unit. Bathwater PUVA may be suitable. In this case the hands and/or feet are soaked in a dilute solution of methoxsalen for 30 minutes, then immediately exposed to UVA. A few patients may be treated with topical PUVA – a psoralens lotion or gel is applied to the affected areas 10 minutes before UVA exposure
PUVA hand unit
What is PUVB?PUVB is the combination of Psoralens and UVB (short wavelength ultraviolet radiation). This is rarely used, as the wavelength that activates the psoralens most effectively is in the UVA range.
Can sunlight be used for PUVA?Where PUVA cabinets are unavailable, some dermatologists have recommended patients are exposed to sunlight after taking psoralens by mouth orapplying psoralens topically. The oral psoralens has usually been trisoralen as this is slightly safer than methoxsalen. Unfortunately, sunlight is unpredictable – it is difficult to get the correct dose. Too little, and it is ineffective. Too much, and a nasty blistering burn may occur.
What is PUVA used for?
PUVA may be used to treat various skin disorders, including:
•Psoriasis •Dermatitis •Vitiligo •Polymorphic light eruption •Cutaneous T-cell lymphoma
The number and the frequency of PUVA treatments will depend on the condition being treated and individual factors. PUVA is used infrequently in New Zealand, as narrowband UVB phototherapy has been shown to be nearly as effective. UVB is also less complicated and less risky.
Side effects of PUVAPUVA has some risks and side effects. BurningAn overdose of PUVA results in a sunburn-like reaction called phototoxic erythema. It is more likely in fair skinned patients who sunburn easily. A burn is most likely 48 to 72 hours after the first two or three treatments. Sensitive areas such as breasts and buttocks may need to be covered for all or part of the treatment. Avoid photosensitizers such as certain oral medications, perfumed cosmetics and applications of coal tar. If the treated skin becomes pink the dose of UVA should not be increased. One or more treatments may be missed. Unfortunately, phototoxic erythema can persist for longer than sunburn from natural sunlight. Moisturizers and painkillers can reduce the discomfort. ItchingTemporary mild pricking or itching of the skin is common after treatment. The skin is often rather dry. Apply a moisturiser frequently. Antihistamine tablets may help. NauseaNausea occurs in a quarter of those treated with psoralens. If it occurs, tell your phototherapy nurse or doctor. Nausea is less if the methoxsalen capsules are taken with food, or the dose is reduced. Antiemetic tablets can be prescribed. TanningPUVA usually leads to tanning which lasts several months. Although the skin appears brown it may still burn easily on sun exposure. Tanning from UVA is not as protective as tanning from combined wavelengths occurring in natural sunlight. Eye damage If the eyes are not protected from UV radiation, keratitis may occur. This results in red sore gritty eyes and can be very unpleasant. Damage to the lens in the eye leading to cataracts is another possible risk. Skin aging and skin cancerExtensive PUVA treatment results in premature aging changes and can increase the chance of skin cancer. •Dry skin and wrinkles •Discolouration: broken blood vessels, freckles, lentigines •Squamous cell carcinoma, and less often, basal cell carcinoma and melanoma Fair skinned individuals or those with previous sun or radiation damage are most at risk. This is not a concern for most patients, who receive PUVA therapy for two or three months only. Patients on long term maintenance therapy should have their skin checked by the specialist at least every 6 months. Bring any new moles, sores which are slow to heal, or growing lumps to the doctor's attention. Usually, but not always, skin cancers are readily curable. When significant ageing changes are evident or skin cancers occur, it becomes unwise to continue PUVA. PregnancyThere is no evidence to suggest that PUVA will damage a developing baby. However, should a patient become pregnant, or suspect she is pregnant, during a course of treatment, we advise our patients to stop PUVA treatment immediately.
Treatment of different skin conditionsPsoriasisPUVA is usually reserved for patients in older age groups, or for those whose psoriasis is either severe or not responding adequately to more conventional forms of treatment. For example, psoriasis with very thick and scaly plaques on trunk and limbs. In approximately 90% PUVA is effective in clearing psoriasis, and can often control it as long as treatments are continued (although this is rarely recommended). Psoriasis in body areas shielded from light (e.g. scalp and body flexures) may not clear satisfactorily with PUVA. Initially most patients have their treatment two or three times a week. The first few exposures will be short (less than 5 minutes). The length of exposure is gradually increased, according to the patient's response, up to a maximum of 30 minutes per session. Few patients require such long exposures, most being controlled with shorter times. Most psoriasis patients will have their psoriasis cleared or much improved after 12 to 24 treatments. At this stage treatments may be reduced to once a week or less. Even without treatment, the skin may remain clear for some months. However, the psoriasis may later flare up again, and PUVA may be recommenced. Those few cases of psoriasis which appear to be resistant to PUVA may still be helped by combining PUVA with other treatments (e.g. ointments or tablets).
Eczema or dermatitis PUVA is occasionally used for severe cases of dermatitis. Frequency and dosage of treatment is similar to that used for psoriasis. However, a course of phototherapy may need to be more prolonged than that generally required for psoriasis. Mycosis fungoides For this rare skin form of cutaneous T-cell lymphoma, PUVA is usually given twice a week at first, using shorter exposures than for psoriasis. When the skin is clear, treatment is given less frequently. If PUVA is stopped, the condition sometimes relapses. Polymorphic light eruption Polymorphic light eruption (PMLE) is a common light sensitivity disorder. A six week course of PUVA in the spring or early summer usually gives patients good protection for the remainder of the summer. A further course of treatment will be necessary if protection is required in subsequent years. VitiligoPatients with vitiligo have areas of completely white skin. PUVA can bring about some repigmentation, particularly for vitiligo of the face, and in dark-skinned patients. Results for other body sites and white-skinned patients are less encouraging. Treatment is usually twice a week for two years. Even then, complete repigmentation cannot be guaranteed and relapse is possible.
“NICE Endorsement for PDT for NMSC
Evidence of efficacy of this procedure for the treatment of basal cell carcinoma, Bowen’s disease and actinic (solar) keratosis is adequate to support its use for these conditions, provided that the normal arrangements are in place for consent,audit and clinical governance.
”Document available at www.nice.org.uk
The size of the problem
•Non-melanoma skin cancers (NMSC) are the most frequently observed neoplasms worldwide •NMSC is the most common type of cancer diagnosed in the UK each year
NMSC include: •basal cell carcinoma •squamous cell carcinoma
•Their incidence has steadily been growing
National guidelinesNational guidelines for the treatment of NMSCDH guidance•Improving Outcomes: A Strategy for Cancer January 2011•Department of Health 'Guidance and competencies for the provision of services using GPs with a special interest (GPwSIs) 2007•The 'Manual for cancer services: skin measures‘ November 2008
NICE Guidance•Improving Outcomes for People with Skin Tumours including Melanoma (update): The Management of Low-risk Basal Cell Carcinomas in the Community May 2010•Improving outcomes for people with skin tumours including melanoma: the manual (2006 guidance) 22 February 2006
Skin sites where lesions are common
Anterior
Posterior
Results of sun damage
Pre-cancerous and cancerous lesions resulting from sun damage:
Actinic (solar) keratosis
Bowen’s disease
Squamous Cell Carcinomas
Basal Cell Carcinomas
Melanoma
Actinic keratosis
AKs are:Potentially pre-malignant skin tumours1
mainly due to long-term exposure to the sun in susceptible persons and may progress to squamous cell carcinoma1
1. Journal of the American Academy of Dermatology 1995; 32:95-98
Actinic keratosis
Red scaly lesions
Single or multiple lesions
Generally asymptomatic
May be difficult to distinguish more severe AK and some SCCs on clinical grounds
Not possible to tell which AKs will progress to SCC1,2
AKs can be treated in primary care
1. Yantsos VA et al. Sem in Cutan Med Surg 1999; 18(1): 3-142. Cockerell CJ. J Am Acad Derm 2000; 42(1) part 2: S11-S17
Prevalence
Actinic keratoses
Prevalence of AK varies with geographyUK prevalence - 5.9%-15.4% of population aged 40+1
Australian prevalence – 40% of the population2
1. Memon et al. Br J Dermatol 2000; 142: 1154-1159 2. Green et al. J Am Acad Dermatol 1988; 19: 1045-1052
Actinic keratosis
1. Adapted from Harvey I et al. Br J Cancer 1996; 74: 1302-1307
The presentation of AK
A few superficial “thin” AKs
Many small but visible AKs, which may be palpated
Multiple “thicker” AKs many of which are quite hyperkeratotic
Bowen’s DiseasePersistent indurated discoid scaly area commonly on lower legs.
Bowen’s disease or carcinoma in situ ie localised neoplastic degneration limited to the epidermis
3-5% risk of Bowen’s transforming to SCC
Bowen’s disease
Basal cell carcinoma
Basal cell carcinoma
BCC accounts for more than three quarters of skin cancers in the UK1
Typical case is on the face of a 70 yr old
Slow growing –non-urgent referral
Locally invasive
Rarely metastasise
1. Cancer Bacup UK
Managing lesions in primary care
Management
Most AKs can be safely managed in primary care thus reducing waiting times for more severe lesions
Treatment options for AK include: Surgery (Curettage or excision)
Cryotherapy
Topical therapy
Photodynamic therapy
Photodynamic Therapy (PDT)
• Metvix® Mechanism of Action
• The active ingredient of Metvix® is methyl aminolevulinate. Metvix®is absorbed selectively by diseased cells and results in accumulation of photoactive porphyrins(PAP)in these cells. Subsequent illumination with a light dose of approximately 631nm wavelength and a total light dose of 37 joules/cm2, leads to the creation of reactive oxygen, which rapidly
eliminates the cancerous cells while leaving the healthy skin unharmed.
Topical PDT therapy
• Key features of Metvix® Methyl aminolevulinate (MAL) Compared to other NMSC treatments
• •Effective in BCC, Bowen’s and AKs• •Selective accumulation in lesions• •Non-invasive• •Minimal scarring • •Fast healing• •Excellent cosmetic outcome compared to surgery • •High patient satisfaction• •Minimal side effects
1. Efudix. Summary of Product Characteristics. May 2004.2. Smith SR & Piacquadio DJ. Poster Presented at the Annual Meeting of AAD,
Washington, USA, February 2004.
TopicalPhotodynamic Therapy (PDT)Clinical Protocol
•Follow clinical protocol•Check diagnosis (histology if present)•Ensure you gain consent (verbal/written)•Take time to explain the procedure. What happens before, during and after light treatment•Repeat treatment after 7 days (if indicated). Follow up after 3 months•Keep clear and accurate records
Infection Prevention & Control•Hand hygiene before and after each procedure•Personal Protective Equipment (PPE)•Equipment is single patient use, where possible•Wipe down equipment (bed, goggles, lamp) and surfaces between patients•Encourage patients to use alcohol hand gel on entering
Results -Photodynamic Therapy before –after 6months –after 3years
Mal PDT in AK: Efficacy
PDTSkin preparation
Demarking of Treatment Area
Application of cream (prodrug)
Application of dressing
Apply a photo-occlusive dressing
PDT Preparing for light illumination
Large Aktilite®Lamp
PDT Photo Fluoresence
Light Therapy
IPL devices in all shapes, sizes, prices and quality
Advantages of IPLs & lasers
• Quick• Very low pain scores• Multiple lesions treated on different body
areas easily• Efficacy comparable to standard PDT
protocols• Usable with ALA or Metvix
Disadvantages of IPL & Lasers
• Expensive devices
• Only really available in dedicated laser units
• Lasers remain painful
PDTPhoto Bleaching
After illumination
PDT Aftercare and Documentation
PDT3 Months Follow Up
LASERS/ IPL
• LASERS
• INTENSE PULSE LIGHT MACHINES
Albert Einstein (1905) used Planck's relationship to explain the results of the photoelectric effect which showed that the energy E of ejected electrons was dependent upon the frequency f of incident light as described in the equation E=hf. It is ironic that in 1921 Albert Einstein was awarded the Nobel Prize for this discovery, though he never believed in particles and acknowledged that he did not know the cause of the discrete energy transfers (photons) which were contradictory to his continuous field theory of matter!
All these fifty years of conscious brooding have brought me no nearer to the answer to the question, 'What are light quanta?' Nowadays every Tom, Dick and Harry thinks he knows it, but he is mistaken. (Albert Einstein, 1954)
History of Lasers
Theodore Harold Maiman
Theodore Harold "Ted" Maiman (July 11, 1927 – May 5, 2007) was an American physicist who made the first laser (Light Amplification by Stimulated Emission of Radiation).
Theodore Harold Maiman
Born(1927-07-11)July 11, 1927
Los Angeles, California
Known for
Inventing, Demonstrating, and
Patenting the World's First
LASER
Notable awards
Stuart Ballantine Medal (1962)
Wolf Prize in Physics (1983)
Japan Prize (1987)
ABSORPTION SPECTRUM
Absorption of energy
Absorption of energy: An atom absorbs energy in the form of heat, light, or electricity. Electrons may move from a lower-energy orbit to a higher-energy orbit.
Ruby LasersA ruby laser consists of a flash tube (like you would have on a camera), a ruby rod and two mirrors (one half-silvered). The ruby rod is the lasing medium and the flash tube pumps it.
2. The flash tube fires and injects light into the ruby rod. The light excites atoms in the ruby.
3. Some of these atoms emit photons.
4. Some of these photons run in a direction parallel to the ruby's axis, so they bounce back and forth off the mirrors. As they pass through the crystal, they stimulate emission in other atoms.
5. Monochromatic, single-phase, columnated light leaves the ruby through the half-silvered mirror -- laser light!
Laser warning sign
Laser ClassificationsLasers are classified into four broad areas depending on the potential for causing biological damage. When you see a laser, it should be labeled with one of these four class designations:•Class I - These lasers cannot emit laser radiation at known hazard levels.•Class I.A. - This is a special designation that applies only to lasers that are "not intended for viewing," such as a supermarket laser scanner. The upper power limit of Class I.A. is 4.0 mW.•Class II - These are low-power visible lasers that emit above Class I levels but at a radiant power not above 1 mW. The concept is that the human aversion reaction to bright light will protect a person.•Class IIIA - These are intermediate-power lasers (cw: 1-5 mW), which are hazardous only for intrabeam viewing. Most pen-like pointing lasers are in this class.•Class IIIB - These are moderate-power lasers.•Class IV - These are high-power lasers (cw: 500 mW, pulsed: 10 J/cm2 or the diffuse reflection limit), which are hazardous to view under any condition (directly or diffusely scattered), and are a potential fire hazard and a skin hazard. Significant controls are required of Class IV laser facilities..
Thank you, any questions?
