Phototherapy
Cynthia Rena Heaton
Margaret Hirsch
Angela Hamilton
LEARNING OBJECTIVES
After studying this chapter, the reader will be able to:
Identify skin disorders that would be appropriate for phototherapy and desired outcomes.
Describe the differences between ultraviolet radiation A (UVA) and ultraviolet radiation B (UVB) light.
Identify the different types of lights and metering equipment.
Describe the different protocols for UVA and UVB therapy.
Identify the appropriate patients for the different therapies.
Describe the different ways to manage side effects of phototherapy.
Understand the purpose of shielding and ways to shield.
Understand the importance of proper use of topical therapy in combination with phototherapy.
Counsel patients that each individual responds differently to phototherapy.
Counsel patients regarding proper and safe care during phototherapy.
KEY POINTS
Phototherapy is an important health care intervention and should be administered with the same precautions as a drug using specialized equipment. A prescription is needed before a treatment is given.
Patient education regarding the importance of home care, protecting against extra ultraviolet light, and consistency of treatments are the keys to success.
The maximum amount of ultraviolet light a patient can receive is measured by risk versus benefit and quality of life.
Documentation of patient education, treatments, and missed treatments is required, as well as patient concerns.
Multiple regulations and guidelines must be considered including state and federal guidelines, Centers for Disease Control, Food and Drug Administration, Joint Commission, and manufacturer recommendations and guidelines.
Treatments are determined by the prescriber, previous dose given, patient response to previous dose, and unit lamp output.
Understand that when switching from UVA to UVB, there is no crossover protection.
I. OVERVIEW
Phototherapy is the exposure of nonionizing radiation for therapeutic benefit; ultraviolet light (UVL) is not visible and is classified by wavelength—UVC, UVB, and UVA; UVB and UVA are used in treating dermatologic diseases. Phototherapy is the use of UVL to clear skin diseases. This is also referred to as photomedicine. Phototherapy is prescribed by dermatologists and other physicians, nurse practitioners, and/or physician assistants.
A. Evolution of phototherapy
1. Broadband (BB) UVB—first used in the 1920s (290 to 320 nm).
2. Full-body cabinets—first used in the 1970s.
3. Narrowband (NB) UVB—first used in the 1980s (311 to 313 nm).
4. Psoralen plus UVA (PUVA) gets Food and Drug Administration (FDA) approval in 1982 (320 to 400 nm).
5. Ultraviolet A1 (UA1), the long-wavelength band of UVA—first used in the 2000s (340 to 400 nm).
B. Ultraviolet light (Figure 6-1)
1. Phototherapy terms
a. Wavelength—the distance measured along the wave from any given point to the next similar point, as from crest to crest (peaks).
b. Nanometer (nm)—the unit of measurement used to describe the distance between wavelengths. One billion nanometers equals 1 m or 39.37 inches.
c. Photons—the energy emitted from the UVL wavelength.
d. Joules (J)—the dosing unit for UVA. One joule equals 1,000 millijoules.
e. Millijoules (mJ)—the dosing unit for UVB.
C. Facts about UVL
1. Longer wavelengths produce fewer photons, resulting in less energy.
2. Shorter wavelengths produce more photons, resulting in more energy.
3. UVL can do one of three things. It can be reflected, transmitted, or absorbed. When UVL is absorbed, photons activate specific cells in the dermis and epidermis called chromophores, resulting in a biological response.
4. Most natural sunlight exposure occurs in the first 18 to 20 years of life, and phototherapy adds to total lifetime accumulation. Overexposure to UVL increases the risk of skin damage. Therefore, risks versus benefits of therapy must be considered.
 FIGURE 6-1. UVL spectrum. |
5. UVL’s therapeutic physiological effects are immune function manipulation, decreased DNA synthesis, and selective cytotoxicity.
D. Common diseases treated with phototherapy
The most common dermatological diseases treated with phototherapy are psoriasis, vitiligo, various types of dermatitis, and cutaneous T-cell lymphoma (CTCL). The goals of phototherapy are different depending on the disease being treated (Table 6-1).
1. Psoriasis: goal is to depress the immune system and slow down T-cell activity, which will then result in thinning of plaques, decreased pruritus, decreased scaling, and induction of remission.
TABLE 6-1 Photoresponsive Diseases | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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2. Vitiligo: goal is repigmentation, which will occur in 50% to 80% of patients.
3. Dermatitis: goal is to depress the immune system resulting in elimination or reduction of pruritus. Improvement of the rash is secondary. This group includes atopic dermatitis, eczema, folliculitis, IRBD or papular dermatitis, and lichen planus.
4. CTCL: goal is to slow the systemic progression of the disease as evidenced by flattening of plaques and normalization of skin pigmentation.
II. PHOTOTHERAPY
UVL waves found in sunlight have a therapeutic effect. The types of UVL used to treat skin diseases are UVB and UVA (Figure 6-2).
A. UVB
UVB is referred to as the sunburn ray. It is 1,000 times more capable of producing erythema than UVA and is dosed in millijoules (mJ). It has shallow penetration into the epidermis, takes a short time to develop erythema (4 to 6 hours), and the erythema resolves quickly (18 to 24 hours). Skin protection against UVB is referred to as hyperplasia, thickening of the top layer of skin.
1. Broadband UVB (BB-UVB) wavelength 290 to 320 nm
a. Must wear goggles, as corneal burns can occur (Figure 6-3).
b. Sunburning spectrum of light, therefore potentially the most damaging.
c. Potential carcinogenesis following long-term exposure.
d. No medications needed as epidermis has sufficient chromophores to absorb UVB. When phototherapy truly indicated in pregnant women, UVB is frequently the type chosen because no additional medications are used with this treatment.
2. Excimer laser UVB-wave length of 308 nm.
a. Treatment twice a week.
b. Emits light that is monochromatic and coherent.
c. Handheld device with a fiber-optic arm allows for targeted application of light while avoiding unaffected skin.
d. Uses a spot diameter of 14 to 30 mm.
 FIGURE 6-2. Energy of UVL. |
 FIGURE 6-3. Eye light absorption. |
3. Narrowband UVB (NB-UVB) wavelength of 311 to 313 nm.
a. Clears lesions faster than BB-UVB.
b. Fewer treatments necessary.
c. Treatment Schedule.
(1) Clearing phase: three to five treatments per week until disease clears.
(2) Maintenance phase: every 9 to 11 days to maintain clearance.
4. Indications (BB-UVB and NB-UVB).
a. Treatment of photosensitive dermatoses.
b. Pregnant women and children may be treated since there are no drugs needed for UVB to be effective.
c. Used for patients with UVA contraindications, such as previous arsenic or x-ray therapy.
5. Absolute contraindications (BB-UVB and NB-UVB).
a. Xeroderma pigmentosum
b. Albinism
c. Porphyria
6. Relative contraindications (BB-UVB and NB-UVB).
a. Can exacerbate photodermatoses.
b. Previous nonmelanoma skin cancers or family history of melanoma.
c. Inability of patient to stand due to physical limitations.
TABLE 6-2 Skin Typing | ||||||||||||||||||||||||
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TABLE 6-3 Comparison of Ultraviolet B Narrowband and Broadband Protocols | |||||||||||||||||||||
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d. Noncompliance with regular treatment schedule.
e. Physically or mentally unstable, debilitated, or intoxicated patients.
7. Dosing (BB-UVB and NB-UVB).
a. Skin type—estimate of patient’s ability to tolerate UVL (Table 6-2).
b. Intensity and dosage length are increased as tolerated per a specific protocol designated by the prescribing provider (Tables 6-3, 6-4 and 6-5; Boxes 6-1 through 6-2).
c. Minimal erythema dose (MED)—smallest amount of UVL needed to produce mild erythema.
(1) Small sections of the patient’s skin are exposed to increasing doses of UVB.
(2) Results are read within 18 to 24 hours.
8. Nursing considerations (BB-UVB and NB-UVB).
a. Always evaluate extent of erythema prior to each treatment.
b. Arms and legs may require extra dosing; if so, all other areas must be shielded.
c. Always question the patient regarding new medications as they may be photosensitizing.
d. Protective goggles must be worn during treatment, genital shields for males.
e. Do not increase dose if it has been 7 days since last treatment (or per facility protocol).
B. UVA
UVA is referred to as the suntanning ray. It is 1,000 times less effective in producing erythema than UVB and is dosed in joules (J). UVA penetrates deep into the dermis, takes a longer time for erythema to develop (12 to 36 hours) and can take days to resolve. Skin protection against UVA is referred to as melanogenesis, which leads to hyperpigmentation (tanning).
TABLE 6-4 Narrowband Treatment Protocol | |||||||||||||||||||||
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TABLE 6-5 Broadband Treatment Protocol | |||||||||||||||||||||
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