UV Radiation

Question 1

True/False. Psoriasis is most responsive to UVA alone.

Answer 1

False. Psoriasis is most responsive to UVA in conjunction with oral or topical psoralen, which makes the body more sensitive to the radiation. UVA in conjunction with the oral or topical psoralen is termed PUVA.

Question 2

The frequency of UV radiation lies between that of what?

Answer 2

It lies between that of x-rays and visible light

Question 3

UV radiation is divided into three bands. What are they?

Answer 3

UVA (wavelengths of 320 - 400), UVB (wavelengths of 290 - 320), and UVC (wavelengths less than 290)

Question 4

UVA is also known as what?

Answer 4

Long-wave UV, and it produces fluorescence in many substances

Question 5

UVB is also known as what?

Answer 5

Middle-wave UV, and it produces the most erythema

Question 6

UVC is also known as what?

Answer 6

Short-wave UV, and it is germicidal

Question 7

The depth of UV radiation is affected by what?

Answer 7

The intensity of radiation reaching the skin, the wavelength and power of the radiation source, the size of the area being treated, the thickness and pigmentation of the skin, and the duration of treatment

Question 8

What is erythema?

Answer 8

Redness of the skin as a result of dilation of the superficial blood vessels caused by the release of histamines. It is one of the most common and obvious effects of exposure to UV radiation.

Question 9

What is MED?

Answer 9

MED (minimal erythemal dose) is determined for each patient before initiating treatment with UV radiation

Question 10

What are some side effects of PUVA treatment?

Answer 10

Epidermal pigmentation and hyperplasia, immune suppression, and the release of free radicals

Question 11

True or False: UV irradiation of the skin is necessary for the conversion of ingested provitamin D to active vitamin D?

Answer 11

True: Because vitamin D controls calcium absorption and exchange, it is an essential vitamin for bone formation, it also influences brain, kidney, intestine, endocrine, immune, and cellular function.

Question 12

In the laboratory setting, can UVC radiation be bactericidal?

Answer 12

Yes, UVC radiation is used to kill bacteria in food and in one small study, UVC was found to be as effective as standard hospital cleaners in removing pathogens from hospital surfaces.

Question 13

A chronic inflammatory skin disease that appears to be based on genetic predisposition.

Answer 13

Psoriasis

Question 14

What is the science behind topical psoralen?

Answer 14

It reduces the appearance of psoriatic plaques by interfering with cell replication and preventing the excessive cell proliferation that causes psoriasis.

Question 15

What is the frequency band of UV for the use of wound healing?

Answer 15

UVC

Question 16

How is UV radiation thought to contribute to wound healing?

Answer 16

The UVC radiation increases epithelial cell turnover, accelerates granulation tissue formation, increases blood flow, kills bacteria, increases Vitamin D production, and promotes sloughing of necrotic tissue.

Question 17

What are the contraindications for the use of UV radiation?

Answer 17

Irradiation of the eyes, skin cancer, pulmonary tuberculosis, cardiac, kidney, or liver disease, systemic lupus erythematosus, fever

Question 18

What are the precautions for the use of UV radiation?

Answer 18

Photosensitizing medications and dietary supplements, photosensitivity, recent x-ray therapy, recent UV radiation

Question 19

What are some examples of photosensitizing medications?

Answer 19

Sulfonamide, tetracycline, and quinolone antibiotics; gold-based medications used for the treatment of RA; phenothiazines used for the treatment of anxiety and psychosis; and psoralens used for the treatment of psoriasis

Question 20

Why are those with fair skin and red hair more sensitive to UV radiation?

Answer 20

These individuals have an accelerated and exaggerated skin response to UV radiation.

Question 21

What are some side effects of PUVA treatment?

Answer 21

Epidermal pigmentation and hyperplasia, immune suppression, and the release of free radicals

Question 22

Chronic exposure to UV radiation, including sunlight, is associated with premature aging of the skin is known as what?

Answer 22

Actinic damage

Question 23

True or False: UV phototherapy has the same level of risk of producing cutaneous cancers as sunlight.

Answer 23

False: UV phototherapy has a low risk of producing cutaneous cancer, except possibly for the skin at the male genitals.

Question 24

An inflammation of the cornea that can be extremely painful that usually appears about 6-12 hours after UV exposure and resolves within 2 days is a symptom of what?

Answer 24

Photokeratitis

Question 25

An inflammation of the insides of the eyelids and the membrane that covers the cornea, results in a sensation of gritty eyes and varying degrees of photophobia, tearing, and blepharospasm is a symptom of what?

Answer 25

Conjunctivitis

Question 26

Chronic UVA and UVB exposures have been associated with the development of what?

Answer 26

Cataracts

Question 27

What can affect a person's sensitivity to UV radiation?

Answer 27

Skin pigmentation, age, prior exposure to UV radiation, the type of UV, and use of sensitizing medications.

Question 28

True or False: The same lamp used to test the patient's skin for sensitivity must be used for every subsequent treatment.

Answer 28

True: because UV radiation can vary significantly with even slightly different frequencies of radiation, which could cause adverse reactions to the treatment.

Question 29

The UV dose grade where there is no change in skin redness occurring in the 24 hours after UV exposure is what?

Answer 29

Suberythemal dose (SED)

Question 30

What is the UV dose grade when the erythema has severe blistering, peeling, and exudation.

Answer 30

Third-degree erythema

Question 31

For patients receiving PUVA therapy, the MED should be determined after they have taken what?

Answer 31

Psoralen

Question 32

Clinicians should avoid excessive exposure during patient treatment. This can be achieved by wearing what?

Answer 32

UV-opaque goggles and UV-opaque clothing.

Question 33

True Or False: Repeated Exposure to UV radiation generally increases sensitivity to UV, and prior exposure does not matter when determining UV treatment dosage parameters.

Answer 33

False: Repeated exposure to UV radiation DECREASES sensitivity and prior exposure SHOULD be taken into account when determining UV treatment dosage parameters.

Question 34

What are factors affecting the intensity of ultraviolet radiation reaching the patient's skin?

Answer 34

1) Inverse square of the distance of the lamp from the patient 2) Power output of the lamp 3) Cosine of the angle of incidence of the beam with the tissue.

Question 35

What are the initial dose recommendations of Ultraviolet B (UVB) for the treatment of psoriasis?

Answer 35

Varies from 50% of the MED to an E1 dose (about 2.5 times the MED), with increases of 10% to 40% at each treatment, depending on the skin response. Treatment is given 3-5 times weekly, and is terminated when the plaque is cleared.

Question 36

What should be documented when using ultraviolet radiation?

Answer 36

1) If and how psoralen was given 2) Area of the body treated 3) Type of UV radiation used 4) Serial number of the lamp 5) Distance of the lamp from the patient 6) Treatment duration 7) ) Response to treatment

Question 37

True or False: One type of ultraviolet lamp is an Arc lamp which is generally small and emits radiation of a consistent intensity.

Answer 37

True

Question 38

True or False: Another type of ultraviolet lamp is a fluorescent lamp which is long and emits higher intensity radiation in the middle than at the ends.

Answer 38

True

Question 39

What kind of lamp is recommended to treat small areas such as the hand, and for treatment of larger body areas?

Answer 39

Single arc lamps are recommended for treating small areas such as the hand, and units incorporating an array of arc lamps are recommended for treatment of larger body areas. Fluorescent tubes are generally not recommended because of the variability of intensity along their length.

Question 40

How long do most UV lamps last?

Answer 40

The useful lifetime of most UV lamps is between 500 and 1,000 hours. Beyond this time the lamp output falls by about 20% compared with the initial output.

Question 41

When is UV irradiation applied when providing PUVA treatments (by drug and topically) ?

Answer 41

When providing PUVA treatment using oral psoralen for psoriasis, the UV irradiation is applied 2 hours after ingestion of the drug. When the psoralen is applied topically, the UV exposure is immediately after the patient is soaked in a bath of weak psoralen solution for 15 minutes.

Question 42

What is the recommended treatment dose of UV radiation when using psoralen to treat psoriasis?

Answer 42

The treatment dose is determined by assessing the MED after the patient has taken the psoralen. Treatment is applied to the whole body and is started at 40% to 70% of the MED and increased by 10% to 40% each week. Complete clearance usually takes about 6 weeks.