Sking hardening in polymorphic light eruption. Comparison of therapeutic effect of UVB hardening in the hospital with treatment at home with Sunshower

Polymorphic light eruption (PLE) is one of the skin diseases caused by
sunlight. Epidemiologic studies have shown that approximately 17% of people
living in the Netherlands suffer from this photodermatosis. The clinical
picture of PLE consists of many intensely itching macules, papules or vesicules
which appear on the exposed skin. These skin changes remain present for several
days or weeks and than they disappear spontaneously - if no new sun exposure is
taking place. In general, PLE can affect the quality of life of the patients
in a very negative way. Some of them do not dare to go outside during a sunny
weather and also the choice of their summer holidays is negatively influenced
by this disease.
Diagnosis of PLE can be established on the basis of patient history and
clinical picture. When there are some diagnostic doubts, histological
investigation can provide some help. Because patients often visit the
dermatologic departments without any visible skin symptoms, the UV provocation
tests can help in the establishing diagnosis. These tests are positive in
60-90% of the patients.

Preventive therapy
In many patients, the exposure to low, slowly increasing dose of UV radiation
can prevent the development of sun allergic reaction. This adaptation response
of the skin (also called hardening) has become the treatment of the first
choice for PLE patients. The hardening consists of a series of UV irradiations
performed 2-3 times a week for several weeks. The patients have to come for
this therapy to the hospital. However, it is necessary that patients take care
of their regular sun exposure themselves after the hardening therapy and in
this way they prolong the hardening effect. However, this is not always
possible; success percentages of 70-90% have been reported for the hardeniogn
therapy. A success percentage of 91% was found in an older study on 68 of our
PLE patients (unpublished). The effect of hardening therapy can disappear
within few weeks.

Sunshower
A Dutch company Sentavi has developed a new product for the bathroom market -
Sunshower. Its variant is named Sunshower Medical. It is a UV producing
apparatus placed in the shower. This UV source (class III) makes it possible to
expose daily the skin to UV radiation during 5-10 min. With this apparatus the
skin should have possibility to build up the adaptation. According to some
recent research, the low dose of UVB radiation causes positive adaptation
response of the skin cells.
The low UV intensity and the possibility to use this instrument at home makes
Sunshower Medical an interesting device that could be used by PLE patients for
their skin adaptation.

In this study we will evaluate the effect of Sunshower Medical device at home
and compare it with the effect of customary UV hardening performed in the
hospital to assess whether the former is not inferior to the latter treatment.
The ultimate goal is to be able to prescribe the treatment at home with the
Sunshower as a good alternative to the treatment in the hospital as the latter
poses quite a strain on the patient because of the many hopital visits
involved.

Recruitment of the patients
The data of more than 100 patients with PLE are present in the Department of
Dermatology. Only the patient with the diagnosis of PLE established by a
dermatologist will be considered for this study. These patients will receive a
short letter asking them whether they would be willing to participate in this
comparative study. For the patients who shall positively respond, appointment
on the out-patient department will be made. At the same time they receive
detailed written information about this study.
The first appointment on the out-patient department
1. The detailed information will be once more discussed with the patient and
questions will be answered. The patient will sign the patient*s
consent.
2. The exclusion criteria will be examined.
3. The blood will be taken for ANF test (only if this routine determination has
not been performed recently)
4. The question forms will be filled in.
The patients who fulfill all the criteria will be coded and randomized for the
UV hardening in the hospital or for home therapy with Sunshower device.

Group A: 20 -25 patients get UV hardening therapy in the hospital. This therapy
will be performed in the Department of Dermatology LUMC and in three other
Dermatology Departments, where the same UV apparatus is present. The hardening
2-times a week will be carried out according to same irradiation scheme for 6
weeks.
Group B: 15-20 patients will be treated at home with Sunshower Medical device.
This apparatus will be placed in their showers free of charge. At the same
time, each patient will receive instructions how to use the apparatus and the
treatment scheme.
All patients also receive record lists where they shall note down development
of unwanted skin reaction causes by the UV irradiation or by the sun.
Provocation tests.
Before the start of skin hardening all patients will undergo UV provocation
tests. In order to reduce the variation of the results, all the provocation
tests will be performed in one hospital only (LUMC).
The first check up.
The first control will take place six week after the start of hardening
therapy. All patients will be monitored in the LUMC. Each patient will be
asked to fill in two questionnaires. In addition, the UV provocation test will
be performed. The patients using home therapy will continue using this therapy.
All patients will be asked to go on with filling in the record lists concerning
unwanted skin reactions.
The second check up.
The second (last) control will take place in the LUMC two months later. Each
patient will be asked to hand over the record list and to fill in the
questionnaires.

The intervention is profilactic treatment of patients with Polymorphic Light
Eruption by a photo-hardening therapy.
Group A of patients, the controle group, receive this treament in the
hospital, whereas group B apply such a treatment to themselves at home while
showering by using the Sunshower device.

There are no unexpected risks for the patients.
Some patients with a very sensitive skin may develop a skin reaction during the
UV hardening in the hospital. In the most cases, the dose of UV will not be
increased the next day, or it can be lowered. The patients using Sunshower
device at home receive written information how to deal with these skin
reactions at home.
The time burden for the patients consists only of additional visits of the
hospital connected with the UV provocation tests.