Author: Jenny Chung, Final Year Medical Student, University of Auckland, New Zealand; DermNet NZ Editor in Chief: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, December 2015.
Heliotherapy is the use of natural sunlight for the treatment of certain skin conditions. It is a form of phototherapy. It is also called climate therapy.
The ultraviolet (UV) part of the sunlight spectrum has beneficial effects in small doses.
The daylight part of the sunlight spectrum can also be useful in the treatment of skin conditions, for example in combination with the photosensitising agent, methyl aminolevulinic acid, for "daylight" photodynamic therapy (PDT) to treat actinic keratoses.
Inflammatory skin conditions treated with heliotherapy are similar to those treated with other forms of phototherapy.
Heliotherapy has been found to reduce the extent and severity of psoriasis and to improve the quality of life for patients. It rarely completely clears psoriasis, and in 10%, sun exposure aggravates psoriasis.
After 2–4 weeks of heliotherapy, there may be an improvement in atopic dermatitis/eczema immediately after treatment and several months afterwards. Note that sunlight can also result in photoaggravated eczema.
Other skin conditions such as vitiligo have also traditionally been treated with sunlight. Heliotherapy may be combined with topical or oral trisoralen (see PUVA), which enhances the effect of sunlight alone, but also increases the risk of sunburn and may cause side effects such as pigmentation.
Disadvantages of heliotherapy include:
Refer to your local reports of ultraviolet radiation levels. In New Zealand, the sun protection alert warns people to protect themselves during certain times of day during the summer months. Global Solar Ultraviolet Index (UVI) describes the level of solar UVR at the Earth's surface in different locations. Safe exposure can be calculated using a smartphone app that displays geographically and Fitzpatrick skin-type specific real-time UV levels.
Traditionally, the Dead Sea has been used as a location for heliotherapy, particularly for psoriasis patients. The sea is approximately 400 m below sea level therefore selectively filters UV radiation, leaving a higher concentration of UVA to UVB than found at sea level. Furthermore, the Dead Sea has an ideal climate to be outdoors, with moderate to high temperatures, low humidity, a large number of sunny/cloudless days and low rainfall per year. This allows the use of the sea for treatment at least 8 months of the year.
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