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Updated: Aug 8, 2026

Minimal Erythema Dose (MED) Testing
Published on: May 28, 2013
Effects of some emollients on the transmission of ultraviolet
Emel Fetil1, Sevgi Akarsu, Turna Ilknur
1Department of Dermatology, Faculty of Medicine, Dokuz Eylül University, Izmir, Turkey. emel.fetil@deu.edu.tr
Background/Purpose:
Various topical agents which can be used in combination with phototherapy may have blocking or enhancing effects. In this in vivo study, the effects of topical petrolatum, basis cream, glycerine and olive oil on the transmission of ultraviolet B (UVB) were investigated.
Methods:
A phototest was performed to determine the minimal erythema dose (MED) on 32 volunteers and the test was repeated with white petrolatum, basis cream, glycerine, olive oil and sunscreen (0.3 cm3/25 cm2). The effects of each agent on MED was determined after 24 h.
Results:
MEDs were increased with the application of white petrolatum and basis cream. However, MEDs were not changed with the application of glycerine and olive oil.
Conclusion:
The application of white petrolatum and basis cream, which have blocking effects, immediately before UVB therapy is not recommended. However, glycerine and olive oil, which does not have any effect, can be used before phototherapy.
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