Narrowband ultraviolet B (NBUVB) phototherapy is a well-established treatment option for a variety of dermatologic conditions. The initial dosage is obtained either by determining the patients’ minimal erythema dose (MED) or their Fitzpatrick skin phototype (SPT). MED determination is a better way to establish the proper initial dose as it is more objective. However, in practice, SPT is more commonly used as it is more convenient, and MED data in Filipinos are scarce.
To establish data determining the MED values of Filipino adults that can serve as a basis to standardize the initial dose of NBUVB phototherapy in a tertiary hospital.
We enrolled 86 volunteers in a cross-sectional analytical study to determine their MED and assess if there is any association between their MED and the participants’ age, sex, skin prototype, ancestry, and daily duration of sun exposure.
The median MED of the participants is 800 mJ/cm2 (IQR 600-800 mJ/cm2). A majority of 38 participants (44.19%) have a MED of 800mJ/cm2 followed by 600mJ/cm2 for 23 (26.74%) participants. There was also a significant association between study participants’ MED with respect to their Fitzpatrick skin type (p=<0.001) and ancestry (p=0.03), but with no association with regards to age (p=0.291), sex (p=0.245), and daily duration of sun exposure (p=0.237).
Majority of the participants have a median MED value of 800 mJ/cm2. Based on this MED value, the initial dosage of NBUVB at 50-70% of the MED would translate to an initial dose of 400-560 mJ/cm2.