Precautions and Contraindications for UV Treatment
Precautions for Use of UV
- Photosensitizing medications and dietary supplements.
Care should be taken when applying UV radiation to patients who are taking photosensitizing medications or supplements. Photosensitizing medications include sulfonamide, tetracycline, and quinolone antibiotics; gold-based medications used for the treatment of rheumatoid arthritis; amiodarone hydrochloride and quinidines used for the treatment of cardiac arrhythmias; phenothiazines used for the treatment of anxiety and psychosis; and psoralens used for the treatment of psoriasis. Certain dietary supplements, including St John's wort, are also known to be photosensitizing. While patients are taking these medications or supplements, they have increased sensitivity to UV radiation, resulting in a decrease in the minimal erythemal dose and an increased risk of burning if too high a dose is used. A patient's minimal erythemal dose must be remeasured if the patient starts to take a photosensitizing medication or supplement during a course of UV treatment.
- Photosensitivity.
- Recent x-ray therapy.
No dose of UV radiation should be repeated until the effects of the previous dose have disappeared. Because of the potential cumulative adverse effects of repeated low-level exposure to UV radiation, it is recommended that clinicians avoid frequent or excessive exposure during patient treatment. This can be achieved by wearing UV-opaque goggles and UV-opaque clothing.
Contraindications
- Irradiation of the eyes
- Exposure of the eyes can be avoided by having the patient wear UV-opaque goggles throughout treatment and by having the therapist wear UV-opaque goggles when at risk of irradiation, such as when turning the UV lamp on or off. Patients taking UV-sensitizing drugs, such as psoralens, should continue to wear UV-opaque eye protection for 12 hours after taking these drugs.
- Skin cancer
- Pulmonary tuberculosis
- Cardiac, kidney, or liver disease
- Systemic lupus erythematosus
- Fever
Adverse Effects
Burning
Burning by UV radiation will occur if too high a dose is used. Burning can usually be avoided by careful assessment of the minimal erythemal dose before initiating treatment and by avoiding further exposure when signs of erythema from a prior dose are still present.
Premature aging of the skin
Chronic exposure to UV radiation, including sunlight, is associated with premature aging of the skin. This effect, known as actinic damage, causes the skin to have a dry, coarse, leathery appearance with wrinkling and pigment abnormalities. It is thought that these changes are primarily the result of the collagen degeneration that accompanies long-term exposure to UV radiation.
Carcinogenesis
Most of the information regarding the carcinogenic effect of UV radiation concerns the effect of prolonged or intense sunlight exposure. Prolonged exposure to UV radiation, as occurs with excessive exposure to sunlight, is considered to be a major risk factor for the development of basal cell and squamous cell carcinoma and malignant melanoma. A review of the literature on the carcinogenicity of UV phototherapy, with and without psoralens, concluded that the therapeutic use of UVB has a low risk of producing cutaneous cancers, except possibly on the skin of the male genitals; however, there is a definite cutaneous carcinogenic risk from PUVA treatment when oral systemic psoralens medications are used. The increased cancer risk with PUVA may be a result of the carcinogenicity of the psoralens or may be a response specific to the wavelength of UV radiation used for this treatment application. PUVA treatments may also exacerbate the effects of previous exposure to carcinogens.