title: Assessment of the usefulness of skin phototype and skin color as the parameter of cutaneous narrow band UVB sensitivity in psoriasis patients.
abstract: BACKGROUND
  Many reports have been released to assess skin types, skin colors and cutaneous sensitivity to broad band UVB or UVA.
  
  
  OBJECTIVE
  This study was performed to investigate the usefulness of skin type and skin color as the parameter of narrow band UVB (NBUVB) sensitivity.
  
  
  METHODS
  The minimal erythema dose (MED) of 40 psoriasis patients was investigated by irradiating several doses ranging from 200 to 1500 mJ/cm2. Before phototesting, the skin color of buttock was measured with a tristimulus colorimeter.
  
  
  RESULTS
  The median and mode value of MED of NBUVB was 950 mJ/cm2. Skin type was well correlated with the MED and there was a significant relationship between the L* value and MED, but not for the a* and b* values.
  
  
  CONCLUSIONS
  The MED value of NBUVB in our study is a basic data to set the phototherapy protocol. Our result showed that skin type and L* value might be useful for predicting the sensitivity to NBUVB irradiation.
authors.affiliation: Department of Dermatology, Seoul National University College of Medicine and Clinical Research Institute, Seoul National University Hospital, Chongo-gu, Seoul, Korea. jaiil@snu.ac.kr
authors.forename: Jai Il
authors.initials: JI
authors.lastname: Youn
authors.forename: Je Young
authors.initials: JY
authors.lastname: Park
authors.forename: Seong Jin
authors.initials: SJ
authors.lastname: Jo
authors.forename: Jong Hyun
authors.initials: JH
authors.lastname: Rim
authors.forename: Yong Beom
authors.initials: YB
authors.lastname: Choe
mesh_terms: D002081:Buttocks; D004307:Dose-Response Relationship, Radiation; D004890:Erythema / Q000209:etiology; D006801:Humans; D011565:Psoriasis / Q000473:pathology*; D012880:Skin Pigmentation / Q000528:radiation effects*; D018709:Statistics, Nonparametric; D014466:Ultraviolet Rays