Last month, the American Academy of Dermatology and the National Psoriasis Foundation released guidelines of care for the management and treatment of psoriasis with phototherapy.

Developed jointly by the AAD and the NPF, the guidelines provide an “in-depth, evidence-based discussion of efficacy and safety for each treatment modality and provide recommendations and guidance for use of these therapies alone or in conjunction with other topical and/or systemic psoriasis treatments.”   Please click here to review the guidelines in full.

The guidelines recognize that systemic and biologic treatments do come with risks of side effects that many patients may be unwilling or unable to assume.  “Phototherapy serves as a reasonable and effective treatment option for patients requiring more than topical medications and/or those wishing to avoid systemic medications or simply seeking an adjunct to a failing regimen.”

Over the next few weeks, we’ll examine the recommendations and share information about the significance for your practice and patients.

Week 1: Treating with Narrow Band UVB

Week 2: Home Narrow Band UVB

Week 3: Combination therapy with Narrow Band UVB

Week 4: Risks of Narrow Band UVB

Week 5: Broadband UVB Overview, Risks & Recommendations

Week 6: PUVA Overview, Risks & Recommendations

Week 7: Summary


Are you new to phototherapy?  If so, please visit our website to learn how phototherapy can benefit your practice and your patients.


Treating with Narrow Band UVB:

Narrow Band UVB (NB-UVB) has proven to be the most effective phototherapy treatment option for thousands of psoriasis patients all over the world. NB-UVB eliminates the harmful UV by emitting wavelengths in a very limited range, generally 311-313 nanometers.  Patients receive the maximum benefits from phototherapy while avoiding the danger of serious burning from sub-erythemal exposure.

The guidelines developed jointly by the AAD and NPF include treating with NB-UVB phototherapy two to three times per week, although skin is more likely to reach clearance more quickly when treated three times per week.  “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.”

Before treatment sessions, it is recommended that a thin layer of emollient, such as petrolatum, is applied to the psoriasis plaques to both increase effectiveness and decrease the potential for UV-induced erythema.  However, a thick layer of emollient may diminish efficacy by decreasing UVB transmission.


Initial Treatment:  The starting dose for NB-UVB therapy can be based on skin type or minimal erythema dose (MED).

To assess skin type, please refer to the chart below:

Skin Type Skin Color Characteristics
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


Once assessed by the prescribing physician and/or phototherapist, guidelines recommended that dosing begins at:


To determine the starting dose based on MED, follow these steps:

  1. Test in a sun-protected region on the patient’s hip or buttock and cover all other areas of the skin. Be certain your patient wears UV blocking eye protection during the test.
  2. Use a skin pen to mark testing areas (approximately 2 x 2 cm) or use a MED patch that can be purchased from Daavlin.

3. Following the chart below, deliver light with all testing areas exposed, covering each after the specific dose of light has been delivered.


Skin Types I and II (mJ/cm2) Skin Types III and IV (mJ/cm2)
250 350
400 500
550 650
700 800
850 950
1000 1100
1150 1250
1300 1400
  1. Instruct your patient to keep the entire area covered for 24 hours, avoiding exposure to natural or artificial UV light.
  2. Assess your patient 24 hours later. The MED is the lowest dose with any identifiable erythema within the test area.

It is not recommended that MED testing be performed on those with skin types V and VI.  Guidelines indicate that these patients should be started at an initial dose of 800 mJ/cm2 and increased as tolerated, according to the recommended protocol.

Subsequent Treatments:

It is recommended that “the effect of skin erythema on UVB dosing will be as follows”:

Missed Treatments:

If your patient missed a treatment, the following schedule is recommended:

Days Missed Treatment Plan
1 week Hold the previous dose constant
1-2 weeks Decrease the previous dose by 25%
2-4 weeks Decrease the previous dose by 50%
Longer than 4 weeks Return to starting dose


Maintenance Therapy:  Once the patient’s psoriasis has cleared, the patient may choose to continue maintenance therapy as a taper or indefinitely.  For prolonged maintenance therapy, the patient should receive a treatment every week or two.  The final dose should be decreased by 25% and held constant for all maintenance treatments.

Next week’s blog post will address the joint recommendations regarding home NB-UVB phototherapy.  Looking for more information now?  Visit our website to learn more today!

For over 30 years, Daavlin has single-mindedly strived to develop products, services and solutions that consistently meet the needs of our customers.  Our SmartTouch™ software can be modified to include the protocols recommended by the JAAD and NPF or to your own specifications.