“Targeted” refers to administration of UV light, via excimer laser, elemental gas lamp, or other sources to a small area of symptomatic skin typically less than 4 cm2. The light administered is typically in the UVB range (between 280nm and 320nm) though it can be in the UVA range as well. Targeted UV phototherapy devices typically consist of a wand or other handheld device connected to a stationary base console. Due to the small treatment area size of the handheld, many dosages are administered to the symptomatic skin, each dosage lasting several seconds.
Prior to targeted UV phototherapy, the minimal erythemic dosage (MED) for each patient is usually determined. Guidelines exist for determining what multiple of the MED will be administered to the patient for treatment. The MED is the amount of UV light that causes reddening of the skin about 8 hours after exposure. The word “erythemic” refers to a reddening of the skin, as in the case of sunburn.
Because the UV light is only administered to the affected skin, healthcare providers can administer intense UV dosages, up to several times as much as the patient’s MED. As the therapeutic effects of the UV light on skin presenting with psoriasis, eczema, and vitiligo are more pronounced because more UV light is administered to them, less visits to the healthcare provider’s clinic are required. For example, plaque psoriasis typically clears in as few as 6 to 10 treatments, generally administered twice per week over 3 to 5 weeks.
While non-targeted phototherapy has been in use for decades, targeted phototherapy is a much more recent advancement in the treatment of psoriasis. It can only be administered by a healthcare provider and is not available for home use.
Many health insurance providers cover both targeted and non-targeted UV phototherapy. The type of psoriasis and severity, as diagnosed by the patient’s healthcare provider, plays a large role in health insurance reimbursement. The patient should always make certain their healthcare provider is aware of how their their Quality of Life (QoL) is impacted by their disease.