The preparation of the patient for phototherapy needs regular monitoring of the equipment and some safety precautions.[9] Before entering the cabinet for treatment eye goggles, proper covering of genitalia and face shield is given for safety purposes. Accurate starting dose determination is done by minimal phototoxic dose/minimal erythema dose testing. Cabinet irradiance should be checked regularly by calibrated radiometer to determine accurate dosimetry. Lamp maintenance should be done by regular cleaning and inspecting the cabinet and lamps and change the lamps when it is needed. After the procedure, the patient should use UV protected glasses until sunset. The patient should also regularly use sunscreen on sun-exposed sites.[11]

The solar electromagnetic spectrum includes UVA(320-400nm), UVB(280 to 320nm), and UVC(<280nm) and is the part between X-rays and visible light.UVR is produced artificially by a technique in which fluorescent tubes containing mercury vapors and phosphorus coating which enable the electric current to pass, then excited electrons of mercury are absorbed by phosphorus coating and then by the process of fluorescence radiations of longer wavelengths reemit. UVA and UVB can be produced by changing of phosphorus.UVA rays penetrate deeper than UVB but UVB is more readily absorbed by DNA than UVA.[12]

Complications of UVB Therapy

Acute effects: The commonest side effects are erythema and burning. Erythema peaks at 12–24 hours and can be associated with pain, swelling, and blistering, more so in skin phenotype I or II, in obese or taking phototoxic drugs. Mild erythema can be managed with topical emollients and steroids. Another complication is Herpes simplex virus reactivation, which commonly affects the lip and occurs more frequently in those with a past history of such outbreaks. Blistering of psoriatic plaques is an uncommon side effect of phototherapy and is usually asymptomatic.[9][2]

Chronic effects: Chronic complications of UVB therapy include photoaging that clinically appears as leathery appearance, xerosis, wrinkling, pigmentary changes, loss of elasticity, and increased fragility. Broad-band UVB has a carcinogenic risk that is not well defined. The carcinogenic risk of NB-UVB, which is being increasingly used for delivering phototherapy, is not fully defined in humans but is less than that of PUVA. Extrapolation from animal studies suggested that NB-UVB is 2–3 times per MED more carcinogenic than BB-UVB. Genital protection during phototherapy is highly recommended.[13]

Complications of PUVA Therapy

Acute effects: Acute PUVA phototoxicity can range from mild erythema to severe pain with edema, blistering, and systemic upset, including malaise and fever.PUVA erythema also lasts longer. A rarer form of phototoxic reaction to PUVA is nail damage with photo-onycholysis or subungual hemorrhage. Nausea is a common side effect in patients treated with oral 8-MOP PUVA. This can be decreased by taking antiemetics or taking the psoralen. Like UVB, PUVA  can also cause the reactivation of Herpes Simplex.

Chronic effects: PUVA lentigines and PUVA keratoses manifest as multiple hyperkeratotic papules on non-sun-exposed sites, for example, the legs, trunk, and sides of the hands, feet, and digits. There is now substantial evidence for the carcinogenic risk of PUVA therapy in large cohorts of patients followed up for prolonged periods of time. There is a marked and dose-dependent increase in Squamous Cell Carcinoma. PUVA can stimulate the growth of melanoma cells and induce melanocytic tumors in animal experiments. As PUVA alters immune function and surveillance, there is a concern that the risk of internal malignancy, particularly of lymphoproliferative neoplasms, may be increased. Psoralens can penetrate the ocular lens, where 8-MOP has been detected in humans. Cataract development following PUVA has been reported in some animal experiments. It is recommended that protective eyewear be worn in individuals with pre-existing cataracts or who may be at increased risk of cataract (e.g., children and patients with atopic eczema.[14]

Phototherapy is a safe, easy, and effective treatment modality in a number of dermatoses with lower cost and lower side effects. As the disease burden of dermatological diseases is high, phototherapy has a superior efficacy as compared to topical or systemic therapy in treating the patients of psoriasis, mycosis fungicides, atopic dermatitis, pityriasis Versicolor, chronic urticaria, palmoplantar pustulosis, and vitiligo. Phototherapy prevents patients from the side effects of systemic therapy because it is a safe alternative.[15]

Patient education has a sole implication in this context, proper explanation of the procedure with special importance to factors that can lead to burning should be adequately explained. Patients must wear UV-blocking goggles for 12 hours following the ingestion of psoralen. Patients should be provided with approved UV protective eyewear. Factors that can lead to inadvertent burning should be discussed with each patient. Obese patients may require a modified treatment protocol, i.e. a lower starting dose, as areas such as the breasts, buttocks, and abdomen are closer to the lamps.[16]

All patient information leaflets should be provided to patients before treatment. Consent should be taken before the procedure and give time to the patient if they change their decision. Long term treatment options, side effects, and other alternative options need to be discussed. Practicalities of treatment should be discussed. Records of patients should be available at each clinic at the start of treatment for review by the consultant and nurse.

The most important risk to staff is exposure to UVB. Staff who conduct dosimetry should wear goggles, face shields, appropriate clothing, and sunscreen (SPF>30) if they have to enter the cabinet with the lamps on. A formal physiotherapist or nurse is undertaken before the start of phototherapy. It must be recorded and includes cumulative doses of phototherapy. There is also a need to do blood tests in a few cases, allergies testing and also keep a record of current medication and special needs assessment.

In cabinets that have combined UVB and UVA lamps, it is essential that the correct tubes are selected for treatment. Male patients should wear appropriate clothing to protect the genitalia. The face (if not involved by the dermatosis being treated) should be shielded with a visor to avoid unnecessary UV exposure. For some indications, whole-body treatment may not be required (e.g., for polymorphic light eruption desensitization, treatment limited to the photo exposed skin may be sufficient.[12]