The term “Phototherapy” literally means the use of light, especially the ultraviolet light, to treat medical conditions. Natural sunlight has been known to be beneficial in certain skin disorders for thousands of years, and it is the ultraviolet part of the radiation produced by the sun that is used in phototherapy, in particular the ultraviolet A (UVA) and ultraviolet B (UVB) wavelengths.
Patients can be treated with the full UVB spectrum (broadband UVB) or just a small part (narrowband UVB) of it. UVA treatment usually comprises of UVA radiation combined with a sensitizer (a chemical that increases the effect of UVA on the skin) called a psoralen (PUVA: Psoralen + UVA). PUVA is also known as photochemotherapy.
Ultraviolet light reduces inflammation of the skin and can help in various inflammatory skin disorders. However, while UV can help skin problems to disappear, this is usually temporary and is not a cure. PUVA is a more potent form of treatment and is usually reserved for people who do not respond to UVB.
Psoriasis treatment is the most common condition treated with ultraviolet light, although a variety of other conditions may also be treated through this procedure including atopic eczema, other forms of dermatitis, polymorphic light eruption, generalized itching, pityriasis lichenoides, cutaneous T cell lymphoma, lichen planus, vitiligo treatment and many others that are less common (disseminated granuloma annulare, morphoea, etc.).
Ultraviolet treatments are usually given in a hospital outpatient department, two to five times a week, in a walk-in cabinet containing fluorescent light bulbs.
The average course lasts between 15 and 30 treatments. The starting dose is worked out either by asking how well you tan in sunlight or by performing a test dose of ultraviolet light on an area of your skin. The first few treatments will often last less than one minute, and the duration of exposure to ultraviolet light will gradually increase, up to a number of minutes.
The amount of skin exposed to the ultraviolet light will depend primarily on the extent of your condition; for most patients all of the skin is exposed to ultraviolet light, except the eyes (which will be protected by goggles) and male genitalia (which should be covered). A visor or face shield may be worn if your face is not affected by your skin condition.
PUVA treatment involves making your skin extra sensitive to UVA by means of a psoralen, which is either taken orally as tablets, 2 hours prior to each treatment session, or by the application of a solution, lotion or gel directly onto your skin (sometimes in a bath – bath PUVA). If a large area of skin is treated with PUVA, you will be required to wear sunglasses that will prevent the exposure of your eyes to natural ultraviolet light for 24 hours from the time of psoralen use.
Your doctor may decide that ultraviolet treatment is not suitable for you if you are very sensitive to sunlight, taking medicines that make you more sensitive to sunlight or if your skin has been damaged by sunlight, sun beds or previous ultraviolet treatments. PUVA treatment may not be used if you havea severe liver or kidney disease. PUVA is contraindicated (not recommended) in pregnancy.
Among some of the things that you need to avoid are:
The short-term side effects of phototherapy include: