Magnitude and duration of UV-B-induced tolerance

Taylor, C. R.

doi:10.1001/archderm.127.5.673

Cited by 9 publications

(8 citation statements)

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“…While cutaneous hyperpigmentation was experienced in the first 2 4 weeks, afterwards there was no evidence of hyperpigmentation although the pigment level was not evaluated clinically at the time of the phototests. The large variation in the baseline MPEo of these patients (skin type 2IV) concords with previous reports (10,29). The highest photoadaptive response was found in subjects with the lowest baseline MPEo; a similar trend was reported for skin type 1-11 as compared to skin type 111-IV (18.7212 versus 15.11211.6) (10).…”

Section: Discussionsupporting

confidence: 88%

Development of cutaneous tolerance to ultraviolet B during ultraviolet B phototherapy for psoriasis

González

Hegyi

Baqer

et al. 1996

Photoderm Photoimm Photomed

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During a schedule of multiple exposures to ultraviolet B radiation (UVB, 280-320 nm), skin develops a reduced sensitivity, variously called tolerance, photoadaptation, accommodation or acclimatization. In this study we have investigated the development of tolerance in the normal skin of a group of psoriatic patients during the course of UVB therapy. Tolerance was assessed by phototests carried out on non-lesional skin as frequently as possible throughout the treatment. Maximum tolerance was developed by the group of individuals most sensitive to UVB, which was twice that of the least sensitive group. The minimal perceptible erythema dose (MPE) increased rapidly in the first 2 weeks (220% per week) and reached a plateau by the eighth week of 800% above the baseline MPE dose. For the more sensitive patients there was a further increase in sensitivity (decrease in MPE dose) after the ninth week of continuous treatment. Tolerance to UVB also involves pigmentation in the first few weeks, but in these patients there was no evidence of hyperpigmentation by the end of treatment. While epidermal hyperplasia is most likely to play a leading role in the development of tolerance to UV, there is no reason to expect this protection to decrease under conditions of continuous exposure. Thus, accommodation to ultraviolet radiation (UVR) is not a monotonically increasing process but appears to alter the accepted reactions of human skin to UVR.

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Section: Discussionsupporting

confidence: 88%

Development of cutaneous tolerance to ultraviolet B during ultraviolet B phototherapy for psoriasis

González

Hegyi

Baqer

et al. 1996

Photoderm Photoimm Photomed

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“…In other words, high skin types photoadapted equally per unit of UVR, but they had greater photoadaptation in absolute terms because they were able to tolerate a bigger dose of UVR to begin with, which enabled a greater stimulus to be applied (Oh et al, 2004). Our findings accord with those of Taylor and Stern (1991), who in a study of 37 patients receiving broadband UVB therapy one, two, or three times per week found that skin typing did not predict the protection factor. One explanation is that skin typing is unreliable (Rampen et al, 1988), but clearly it cannot be totally unreliable because it is associated with the MED (Figure 1, Po0.001).…”

Section: Discussionsupporting

confidence: 73%

“…For these reasons, protection factors will be higher than the AF we have calculated. Studies with UVB have typically found, after at least nine sessions, protection factors of 2-13 (Cripps, 1981;Schothorst et al, 1984;Taylor and Stern, 1991;Gonzalez et al, 1996;Sheehan et al, 1998Sheehan et al, , 2002de Winter et al, 2001). Differences in photoadaptation by body site have not, to our knowledge, been reported (Waterston et al, 2004).…”

Section: Discussionmentioning

confidence: 91%

“…There is evidence that can be used in support of the first (Taylor and Stern, 1991;Oh et al, 2004), second (Gonzalez et al, 1996;Kollias et al, 1996), and third (Sheehan et al, 1998(Sheehan et al, , 2002Jasim and McKenna, 2005) of these possibilities. We therefore retrospectively studied patients having a standard phototherapy regimen comprising twice-weekly narrowband UVB (NB-UVB) with a starting dose of 70% of the MED followed by 20% increments, and sought a relationship between erythemal episodes and skin type or MED.…”

Section: Introductionmentioning

confidence: 99%

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Photoadaptation during Narrowband Ultraviolet-B Therapy Is Independent of Skin Type: A Study of 352 Patients

Palmer

Aquilina

Milligan

et al. 2006

Journal of Investigative Dermatology

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Understanding how photoadaptation differs between individuals is important when considering susceptibility to the beneficial and harmful effects of sunlight exposure and when determining optimal phototherapy regimens. Most narrowband UVB (NB-UVB) regimens start with 70% of the minimal erythema dose (MED) with 20% increments at each treatment thereafter. We retrospectively studied 352 skin types I-IV psoriatic patients having twice weekly treatment with this regimen. Patients with high skin types tended to have high MEDs (P<0.001). By session 20 the proportion of patients who had developed erythema was approximately 60% regardless of MED. Among patients who developed erythema, the number of treatments before erythema occurred did not differ between skin types (P=0.33). We conclude that patients with high skin types photoadapt approximately equally per physical unit of UVR in comparison to those with low skin types, but they have greater photoadaptation in absolute terms because they are able to tolerate a higher initial dose of radiation. Differences in skin type or MED are not associated with clinically important differences in tendency to erythema during a standard 70/20% NB-UVB twice-weekly regimen. This regimen is suitable for all skin types I-IV patients regardless of skin type or MED.

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“…The duration of this increase in tolerance is, however, short. This is the reason why less than one MED, usually 70% of MED, is preferred to be given at each session of phototherapy (8).…”

Section: Discussionmentioning

confidence: 99%

Different narrowband UVB dosage regimens in dark skinned psoriatics: a preliminary study

Youssef

Mahgoub

Mashaly

et al. 2008

Photoderm Photoimm Photomed

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Magnitude and duration of UV-B-induced tolerance

Cited by 9 publications

References 0 publications

Development of cutaneous tolerance to ultraviolet B during ultraviolet B phototherapy for psoriasis

Development of cutaneous tolerance to ultraviolet B during ultraviolet B phototherapy for psoriasis

Photoadaptation during Narrowband Ultraviolet-B Therapy Is Independent of Skin Type: A Study of 352 Patients

Different narrowband UVB dosage regimens in dark skinned psoriatics: a preliminary study

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