Management and treatment of psoriasis with phototherapy: AAD/NPF guidelines

American Academy of Dermatology and National Psoriasis Foundation have jointly released guidelines for Management and treatment of psoriasis with phototherapy. The guidelines have been published in the Journal of American Academy of Dermatology.

Psoriasis is a chronic inflammatory disease involving multiple organ systems and affecting approximately 3.2% of the world's population. Although many patients with psoriasis may be capable of adequately controlling their disease with the use of topical treatments alone, often these interventions are insufficient and disease severity dictates the need for alternative options.

• NB-UVB refers to wavelengths ranging from 311 to 313 nm, which are widely used for the treatment of generalized plaque psoriasis.


• The starting dose for NB-UVB therapy can be based on skin phototype or minimal erythema dose (MED).


• A frequency of twice or thrice weekly is effective and is therefore recommended.


• A frequency greater than thrice weekly results in little added benefit, while at the same time exposing the patient to a higher total dose of UVB radiation and greater risk of ultraviolet (UV)-induced erythema.


• Although both twice-weekly treatment and thrice-weekly treatment eventually achieve clearance in equal proportions, twice-weekly treatments appear to take about 1.5 times longer to achieve skin disease clearance as compared with thrice-weekly treatments.More specifically, patients receiving twice-weekly NB-UVB treatments achieve clearance in a mean of 88 days compared with 58 days for those receiving 3 treatments per week.


• Maintenance treatment sessions after improvement or skin clearance may be spaced farther apart, usually once weekly.


• Dose category-Estimation of initial NB-UVB dose by skin type will be performed by skin type, as assessed by the prescribing physician and/or the phototherapist, as follows:
  
  
  
  • Skin types I and II: 300 mJ/cm²
  
  
  • Skin types III and IV: 500 mJ/cm²
  
  
  • Skin types V and VI: 800 mJ/cm²
  
  
  
  


• Determination of MED, subsequent visits, maintenance therapy, and maximum dose for NB-UVB phototherapy
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

  I	White, very fair, red or blond hair, blue eyes, freckles	Always burns, never tans
  II	White; fair; red or blond hair; blue, hazel, or green eyes	Usually burns, tans with difficulty
  III	Cream-white, fair with any eye or hair color	Sometimes mild burn, gradually tans
  IV	Brown, typical Mediterranean white skin	Rarely burns, tans with ease
  V	Dark brown, Middle Eastern skin types	Very rarely burns, tans very easily
  VI	Black	Never burns, tans very easily

  
  


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  Determination of MED*
  MED should be tested in a sun-protected region on the hip or buttock. All other areas of the skin should be covered. The patient should wear eye protection during delivery of the UV doses The tested areas should be uniform in size, approximately 2 × 2 cm, and marked with a skin pen to identify the tested area The following dosage schedule should be used depending on skin type:

  
  


• Determination of MED, subsequent visits, maintenance therapy, and maximum dose for NB-UVB phototherapy

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   Start the delivery with all testing areas open and cover after the specific dose of light has been delivered

   
   


2. Instruct the patients to keep this area covered for the next 24 h, avoiding exposure to natural or artificial UV light


3. The patient should return 24 h later. The MED is the lowest dose with any identifiable erythema within the tested area

*Note: MED testing should not be performed in patients with skin types V and VI. These patients should be started at an initial dose of 800 mJ/cm² and increased as tolerated according to the protocol below.

• Subsequent visits

In subsequent visits, patient response to phototherapy is assessed by the degree and duration of skin erythema and possible subjective symptoms of burning (stinging, pain, or itch)

The effect of skin erythema on UVB dosing will be as follows:

1. Minimal erythema lasting <24 h following treatment: increase dose by 20%


2. Erythema persistent for >24 h but <48 h: dose held at previous level until erythema lasting <24 h


3. Erythema lasting >48 h: No treatment on that day followed by return of dose to the last lower dose that did not cause persistent erythema