UVB 311 nm Light Therapy

UVB 311 nm light therapy (synonym: narrow spectrum UVB; 311 nm UVB) belongs to the subfield of UVB phototherapy, which in turn is a derivative of light therapy. The method is used primarily in dermatology (the study of skin diseases) for the treatment of psoriasis, where it has achieved great success. Phototherapy is the treatment of skin diseases with ultraviolet light. The spectrum of UV light is divided into UVC (200-280 nm), UVB (280-320 nm), UVA1 (320-340 nm) and UVA2 (340-400 nm). UVB phototherapy can be performed by a UVB broad-spectrum lamp or by a UVB narrow-spectrum lamp that radiates at the defined wavelength of 311 nm. UVB 311 nm light therapy is a scientifically recognized proven procedure used to treat dermatologic conditions.

Indications (areas of application)

  • Psoriasis vulgaris (psoriasis).
  • Atopic eczema (synonyms: atopic dermatitis, atopic dermatitis and endogenous eczema) – disease caused by an excessive reaction of the immune system against allergens. Symptoms include itching, redness, scaling, oozing and crusting.
  • Mycosis fungoides – a cutaneous (located in the skin) T-cell lymphoma, which is a malignant (malignant) degeneration of cells belonging to the immune system (develops slowly over several years; in early stages there is pruritus (itching) and a red, scaly patch, darker spots may also develop).
  • Parapsoriasis en plaques – a chronic skin disease whose cause is unclear, but similar to psoriasis.
  • Pruritus, prurigo – disparate group of diseases whose common feature is itching.
  • Prophylaxis of polymorphic light dermatosis (PLD) – so-called sun allergy, prophylaxis is aimed at desensitization (habituation) of the skin.
  • Vitiligo – white spot disease characterized by the autoimmune-induced demise of melanocytes (cells that produce the brown skin pigment) at defined locations

The procedure

Treatment with UV light poses a risk to the integrity of the patient’s skin. To make the therapy as gentle as possible, either the photo skin type (corresponding to the sensitivity to light) or the so-called MED is determined first. MED stands for “minimal erythema dose” and is defined as the lowest radiation dose that causes just visible erythema (redness). This value makes it possible to assess the individual characteristics of the skin after 24 hours. According to these characteristics, the first dose for therapy is determined. The photo skin types are classified as follows (classification according to Fitzpatrick):

  • I – very light skin, freckles, light eyes, red hair (Celtic type); very frequent sunburn; skin does not tan after
  • II – fair skin, light eyes, blond hair (Scandinavian type); often sunburn; skin tans minimally
  • III – light brown skin, light brown to dark brown hair, light or brown eyes (Central European, Mediterranean type); occasional sunburn; skin tans well
  • IV – medium brown skin, dark eyes, dark hair (Mediterranean type); rarely sunburn; skin tans very well
  • V – dark brown skin, etc. (Asian type, Oriental, Latin American); very rarely sunburn; skin tans very well.
  • VI – black skin (Africans); extremely rare or no sunburn; very dark pigmentation.

UVB 311 nm light therapy (narrow spectrum) has been shown to be superior to UVB broad spectrum therapy for certain conditions (e.g. psoriasis – psoriasis). This is mainly due to the better efficacy with less erythema formation. Furthermore, good results have been shown for treatment in combination with medication. The patient is usually treated three to five times a week over a period of about 4-8 weeks. In principle, the dose can be increased, but it is always based on the erythema threshold and should only be increased with caution.