• Light therapy: Light therapy is a first line treatment for moderate to severe psoriasis, either alone or in combination with medications. It involves exposing the skin to controlled amounts of natural or artificial light. Repeated treatments are necessary. Talk with your health care provider about whether home phototherapy is an option for you.
• Sunlight: Brief, daily exposures to sunlight (heliotherapy) might improve psoriasis. Before beginning a sunlight regimen, ask your health care provider about the saf:est way to use natural light for psoriasis treatment.
• Goeckerman therapy: An approach that combines coal tar treatment with light therapy is called the Goeckerman therapy. This can be more effective because coal tar makes skin more responsive to ultraviolet B (UVB) light.
• UVB broadband: Controlled doses of UVB broadband light from an artificial light source can treat single psoriasis patches, widespread psoriasis and psoriasis that doesn't improve with topical treatments. Short-term side effects might include inflamed, itchy, dry skin.
• UVB narrowband: UVB narrowband light therapy might be more effective than UVB broadband treatment. In many places it has replaced broadband therapy. It's usually administered two or three times a week until the skin improves and then less frequently for maintenance therapy. But narrowband UVB phototherapy may cause more-severe side effects than UVB broadband.
Courtesy: Mayo Clinic