The Photobiology unit offers diagnosis and treatment for certain types of skin cancer and also performs investigations to check for different types of allergies to sunlight and artificial light. Conditions are treated with range of medicines or you may be referred for Phototherapy to harden the skin gradually with UV lamps.
Patients suspected of having an allergy to sunlight have an hour long discussion with a consultant Dermatologist where photographs of their skin reactions are shared, and a very detailed clinical questionnaire if completed. A diagnosis is often made at this appointment and medicine and/or sunscreen prescribed. Sometimes further tests or follow-up discussions with a dermatologist are scheduled before a diagnosis can be made..
Around thirty different product samples are applied to the skin to check for allergy to sunscreen and it's ingredients. A duplicate set is irradiated with UVA light to see if the combination of light and the product is causing irritation or allergy.
Two slightly different lamp s are used on three consecutive days to see if they provoke a response. The light is much less powerful than sunlight and so wouldn't be expected to cause sunburn or tanning even in patient's with the fairest skin types.
A monochromator divides artifically created sunlight into many different wavebands to try and pin point the exact energy (or colour) of light that is causing a reaction. A range of doses at each waveband is required to find the individual threshold to each waveband.
Blood samples are taken from each patient to check for the presence of certain antibodies and enzymes, and to quantify vitamin D levels. A urine sample is also checked for a specific enzyme called porphyrin.
Photodynamic therapy (PDT)
Patients with non-melanoma skin cancer or precancerous conditions attend the unit for treatment with ointments and lamps. Sometimes the ointment is applied and the patient is asked to go outside for a specific time period-this is called daylight PDT.
A small sample of the top few layers of skin is taken and sent to the lab for histological analysis. This can identify the presence of unusual cells or a distorted structure of the certain layers that can be matched to a specific condition.
Blood and Urine samples
Samples of blood and urine are also sent to the lab where the presence of antibodies and enzymes can be identified. This supports diagnosis and can indicate how severe certain conditions are. The level of vitamin D is also checked which is low in a large number of people in the UK whether or not they have a skin condition. Where this is low, a supplement can be prescribed.
The patient will be asked to attend for four consecutive days ans spend up to four hours in the unit, however, on some days, the visit is often just an hour or so. There are two canteens in the hospital and a number of vending machines in the Dermatology department and breaks can usually be incoroprated.
Photobiology Unit, Barnes Building
Patients can be referred by a consultant Dermatologist or sometimes directly from a G.P.