What is light therapy 1

Light therapy (UV therapy and photo diagnostics)

Senior Physician:

PD Dr. med. Hannelore noon

Tel. 06421- 58 62947

In the area light therapy are the UV process offered and
tests are carried out to check the sensitivity to light.


Light therapy includes all treatment methods in which an effect on the skin is achieved through radiation from the range of the sunlight spectrum.

This can be done by amplifying the light in the form of LASER radiation. An argon laser is available here in the clinic for this purpose.

With a special pre-treatment, visible light can be used in photodynamic therapy (see under General> Day Clinic).

Furthermore, the ultraviolet "light" (UV) is used to treat various skin diseases as UV therapy (or phototherapy) and targeted examinations for UV sensitivity (photodiagnostics) can be carried out.

  • UV radiation (ultraviolet "light")

These are invisible parts of the solar radiation. UV radiation can also be generated artificially using special lamps and applied to the skin. A distinction is made between UVA, UVB and UVC. The latter part, the UVC radiation, is very short-wave and is filtered out of the sunlight by the earth's atmosphere. In UV therapy, UVC radiation is of no importance; because the devices used here do not emit any UVC (and also no X-rays). Partial or full-body devices that emit radiation in the short-wave UVB range (280-320nm wavelength), in the narrowband UVB range (UV light with a wavelength of around 311 nm) and in the longer-wave UVA range (from 320-400 nm) are used therapeutically Wavelength).

  • The effect of UV radiation on the skin

The short-wave UVB penetrates only into the upper skin (epidermis), while UVA reaches the connective tissue layer underneath (corium / dermis). The very long-wave UVA1 component is particularly effective here.
UVB thickens the protective horny layer on the surface of the skin and pigment formation is stimulated, the skin turns brown. Excessive use causes sunburn, i.e. reddening and blistering. The severity of the sunburn reflects the damage to the important basal cell layer of the epidermis. Excessive exposure to UVB radiation can lead to preliminary stages of skin cancer (so-called actinic or solar keratoses), skin cancer (squamous cell carcinoma) and basal cell carcinoma. These tumors that develop on skin exposed to UV light can, if recognized in good time, be treated well and then have no adverse effect on the life expectancy of those affected.

UVA briefly darkens the pigment present (instant pigmentation), otherwise there is initially no change in the skin. With long-term use, UVA can cause structural changes by penetrating the corial connective tissue, including strengthening of skin folds and increasing skin aging. Excessive exposure to UVA appears to promote the development of melanoma, a malignant pigment cell tumor (but it is not the only cause).

UV radiation is involved in the complete synthesis of vitamin D.
Another effect is a weakening of immune cells in the skin, i.e. the Langerhans cells in the epidermis and the lymphocytes in the epidermis and corium.
Cell division is also inhibited by UV light.

  • The different UV treatment methods

At the moment there is the possibility of treatment with UVA, UVB, UVB 311 nm narrow band and PUVA in this clinic. PUVA treatment, known as photochemotherapy, involves treatment with a "photosensitizer" (P), a substance that makes the skin sensitive to light, and the subsequent UVA exposure of the skin.

- Cream PUVA A cream containing the light sensitizer (methoxsalen, sometimes khellin) is used to apply cream to the diseased skin areas (thin, visible layer). The cream should work for 30 minutes, then it is removed with cellulose. The cream should not get into adjacent healthy skin areas. The UVA light irradiation takes place immediately after the half-hour treatment, no later than 1 hour after applying the cream.

- Bath PUVA A 20-minute bath in warm water (at a comfortable temperature) to which the nursing staff has added a certain amount of the light sensitizer (methoxsalen) prepares the skin for the light treatment. After the bath, the skin is patted dry, not rubbed. Immediately afterwards (within an hour at the latest) the UVA light treatment takes place. The bathed areas remain light-sensitive for the course of the day, i.e. (severe) sunburns can occur in the event of additional exposure to sunlight or solarium.

- Oral PUVA Methoxsalen tablets (Meladinine®) are taken in the agreed amount, depending on body weight. This makes the skin and eyes sensitive to light, including UV light coming through the window panes. UV protective goggles must therefore be worn all day long. Treatment with UVA takes place two hours after taking the medication. Additional exposure to sunlight or solarium must be avoided at all costs, as this could cause damage, similar to very severe sunburn, with blisters and peeling of the skin.

  • Selection of the appropriate UV treatment

The more superficial diseases take place on the skin, the more likely a UVB or UVB-311 treatment is the most suitable method. This form of treatment is used primarily for psoriasis (psoriasis vulgaris, psoriasis guttata and punctata), atopic dermatitis (neurodermatitis) and other types of eczema, for small-nodular forms of parapsoriasis and itching (pruritus) and as a preventative treatment for UV hypersensitivity ( "Sun allergy") is used.

Above all, pure UVA has a beneficial effect on severe itching, which can be present in atopic dermatitis (neurodermatitis), diabetes, liver damage and renal insufficiency.

In numerous inflammatory and proliferative diseases in which the epidermis and especially the corium is affected, the skin changes improve under PUVA therapy, whereby it must be decided in individual cases whether oral PUVA, bath PUVA or cream PUVA treatment is used. The well-responding diseases include the following inflammatory diseases: long-standing psoriasis vulgaris (psoriasis), lichen planus (lichen planus), severe forms of atopic dermatitis (neurodermatitis), hand and foot eczema, localized scleroderma (morphea) and scleromyxedema and some forms of one severe itching and certain forms of intolerance to sunlight (photodermatoses); Granuloma annulare and necrobiosis lipoidica respond moderately well. The use of PUVA is considered to be the drug of choice for parapsoriasis (large-scale form) and for the initial stages of T-cell lymphomas (e.g. mycosis fungoides). Findings can be improved in lymphomatoid papulosis, mastocytosis (urticaria pigmentosa) and graft-versus-host reactions after bone marrow transplants.
In severe forms of atopic dermatitis (neurodermatitis), in scleroderma and scleromyxedema, particularly good results are achieved on the skin with UVA1. To carry out this treatment, a special device is required, which is expected to be available in this department from 2005/2006.

MPD test
The UVB dose on the field that just barely shows reddening after 24 hours corresponds to the minimum erythema dose (MED). This value provides information about the individual UV sensitivity to UVB and averages 0.06 J / cm┬▓ UVB.

The determination of the minimum phototoxic dose (MPD) is carried out for whole-body PUVA treatment in order to obtain information about the lowest UVA dose that just causes reddening in this combination. With this information, the further PUVA treatment can be better planned. To carry out this test, it is first necessary to use the photosensitizer according to the intended treatment principle in the necessary exposure time (as stated for cream PUVA, bath PUVA or oral PUVA therapy), then UVA is applied in increasing doses to small ones Test fields checked. The final test result can only be expected in 4 days, the results are read and documented every day.

  • Photodermatoses and light allergy

In principle, similar tests are carried out to clarify hypersensitivity to UV or visible light. If there is a history of drug-related light oversensitivity, the substances in question can be tested as a patch test (patch test) on the skin and the areas can be irradiated with UVA light after 24 hours. On the 3rd and 4th day this "photo-patch-test" is then read and compared with a simple patch test carried out at the same time.

  • Start and end of UV therapy

An initial appointment in the field of UV therapy and UV diagnostics can be arranged directly (Tel. 06421-58 62947) if there is a referral specifically for UV treatment or photo diagnostics. Otherwise there is a possibility of dealing with a skin disease in the University outpatient clinic this clinic (by appointment, Tel. 06421-58 62940, weekdays). The doctors working there check whether phototherapy or photodiagnostics is indicated and, if necessary, ask you to come to the area light therapy to go.
After the end of a UV treatment, which lasts on average 15 to 20 appointments, a passport with precise information on the therapy carried out is handed out.