Assessment of the usefulness of skin phototype and skin color as the parameter of cutaneous narrow band UVB sensitivity in psoriasis patients.
ABSTRACT Many reports have been released to assess skin types, skin colors and cutaneous sensitivity to broad band UVB or UVA.
This study was performed to investigate the usefulness of skin type and skin color as the parameter of narrow band UVB (NBUVB) sensitivity.
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.
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.
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.
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ABSTRACT: Background Assessment of minimal erythemal dose (MED) for individual patients has been used to guide the narrowband Ultraviolet B (NB-UVB) phototherapy, which sometimes causes discomfort and additional time. The L* value (the lightness of color in Commission Internationlale de l'Eclairge L*a*b* color scale) measured by colorimeter was shown to be useful for predicting sensitivity to NB-UVB irradiation. Objective To compare the efficacy and safety of NB-UVB phototherapy between 50% of MED and colorimetric L* value starting dose regimens for skin phototype III-V Korean patients with psoriasis. Method Twenty seven patients determined starting doses based on colorimetric L* value, and 27 patients based on 50% of MED. Since correlation analysis showed that L* value had the most significant association with MED compared with skin phototypes, a*, and b* values, we designated starting doses of L* value regimen as follows: 300 mJ/cm(2) (L* >66), 400 mJ/cm(2) (62 < L*≤66), and 500 mJ/cm(2) (L*≤62). Results There was no significant difference between two groups in clinical efficacy including response rate, mean number of sessions, duration of treatment, maximum dose and cumulative dose until achieving the state of near clearance. The proportion of adverse effects was not also significantly different. Conclusions NB-UVB starting dose determination based on colorimetric L* value was comparable with conventional MED based regimen in efficacy and safety for skin phototype III-V patients. Since it provides much convenience and ease for both patients and physicians, colorimetric L* value could partly substitute the MED checking methods in NB-UVB phototherapy.Journal of the European Academy of Dermatology and Venereology 02/2012; · 2.69 Impact Factor
Article: Minimal Erythema Dose (MED) Testing.[Show abstract] [Hide abstract]
ABSTRACT: Ultraviolet radiation (UV) therapy is sometimes used as a treatment for various common skin conditions, including psoriasis, acne, and eczema. The dosage of UV light is prescribed according to an individual's skin sensitivity. Thus, to establish the proper dosage of UV light to administer to a patient, the patient is sometimes screened to determine a minimal erythema dose (MED), which is the amount of UV radiation that will produce minimal erythema (sunburn or redness caused by engorgement of capillaries) of an individual's skin within a few hours following exposure. This article describes how to conduct minimal erythema dose (MED) testing. There is currently no easy way to determine an appropriate UV dose for clinical or research purposes without conducting formal MED testing, requiring observation hours after testing, or informal trial and error testing with the risks of under- or over-dosing. However, some alternative methods are discussed.Journal of Visualized Experiments 01/2013;
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ABSTRACT: The spectrophotometer is well known to be a useful tool for estimating the objective minimal erythema dose (MED) during planning of phototherapy protocol. However, only a few spectrophotometric values are used to evaluate the erythema and pigmentation of the MED site during phototesting. To determinea new meaning of the relationships among spectrophotometric values during phototesting. Twenty-five patients with psoriasis and 23 patients with vitiligo were selected before undergoing narrowband ultraviolet B phototherapy. We interpreted the gross findings of erythema and measured the L(*)a(*)b(*) values using a spectrophotometer at each phototest spot. We compared MEDs, basic spectrophotometric values (L(*)a(*)b(*)), and b(*)/L(*) values separately according to skin type, and determined the correlation of each spectrophotometric value and the correlation between a(*) and b(*)/L(*) values. Among L(*)a(*)b(*) values, only b(*) values showed a statistically significant difference between the type III and IV groups (p=0.003). There was a positive correlation only between MEDs and b(*) values (p<0.05). The average b(*)/L(*)value in the type IV group was significantly higher than the type III group (p<0.05). The higher b(*) values in type IV skin indicates that skin tanning develops more prominently than type III. The correlation between MEDs and b(*) values may signify that the skin pigmentation status is deepened with the higher MEDs. The difference in b(*)/L(*)values between type III and IV skin reflects that the b(*)/L(*)value is thought to be an index of tanning. The a(*) value, known as an index of erythema, does not influence the degree of tanning.Annals of Dermatology 02/2014; 26(1):17-25. · 0.61 Impact Factor