What is photosensitivity testing?
Photosensitivity testing consists of testing your skin with a variety of different wavelengths of light, to help your doctor determine whether your skin condition is caused or made worse by exposure to sunlight.
What does photosensitivity testing involve?
Three visits to hospital are usually required.
A series of tests using different types and strengths of mostly ultraviolet light will be applied to the skin of your back and arm, although other areas of your skin may also be selected. The positions of the test areas will be identified with a skin marker pen. You may also be asked to have a blood test on that day.
Allow up to 3 hours for the first visit.
The second visit is the following day. The consultant will look at the results of the skin tests and may decide further light tests are needed. They will be carried out at that time. If this is the case, a third visit on the next day is also required to read the results.
Please allow at least half an hour for the tests and discussion of the results on the 2nd and 3rd days.
It is important you attend for all 3 days if required.
Do
- Bring a list of any current medications you are taking, including over-the-counter medicines.
Do not
- Wear your best clothes as the marker ink may stain.
- Expose your skin to strong sunlight immediately after the tests.
- Attend for these investigations if you have been on a sunny holiday in the last 6 weeks.
If you are taking antihistamine tablets, these should not be taken for 48 hours before your tests.
Rearranging your appointment
If you need to rearrange an appointment, please telephone (we would appreciate as much notice as possible.
What side-effects may occur?
On the test sites, you may notice very small red marks develop later in the day. This is normal. The tests may also induce the problem you are experiencing in the small test areas, approximately (4 cm x 4 cm). There may also be an increase in skin pigmentation at some of the testing sites, although this resolves over a few weeks.
Storage of test results
We will record the information about your test results in an anonymised form on a secure database for audit purposes, in accordance with good medical practice. The anonymised data may also be used for research.
Failure to attend
Failure to attend your appointments without informing us will result in you being discharged back to your referring doctor.
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