Safe, mild ultraviolet-B exposure: An essential human requirement for vitamin D and other vital bodily parameter adequacy: A review.

The enigma of skin sunburning, skin ageing and skin cancer and essential vitamin D production both resulting from solar ultraviolet-B (280-315 nm) (UVB) exposure has long puzzled photobiologists. Advice to patients by non-photobiological clinicians is now often to sunbathe to acquire vitamin D adequacy. However, modern work shows only mild UVB exposure is needed to maintain satisfactory levels, which have been demonstrated as very similar in summer and winter from about 25° to 70° north. Even very careful high protection factor 15 sunscreen use does not prevent adequate production, although it is slightly reduced, such that obsessive use of very protective screens of 50 + might. Dark skin pigmentation too usually at most minimally impairs production. However, confinement indoors and widespread clothing cover can, but oral supplementation overcomes any such deficiency. Thus, vitamin D adequacy needs just mild regular UVB skin exposure well under sunburning levels, unlikely to cause significant skin damage. This suggests mild UVB exposure may also be needed for other bodily requirements, which is indeed so. Thus, it also prevents the development of contact dermatitis and polymorphic light eruption through suppressing adaptive immunity. It also prevents the occurrence of multiple skin infections resulting from this suppression through stimulating innate immunity and cutaneous bacterial defensin production. Finally, blood pressure is reduced through low-dose UVB-induced production of the vasodilator nitric oxide (though UVA, 315-400 nm, is more efficient). Thus, mild UVB exposure is important for several aspects of internal health, whereas high-dose exposure is extremely detrimental to cutaneous health.

Audit of the use of psoralen photochemotherapy (PUVA) and narrowband UVB phototherapy in the treatment of psoriasis.

BACKGROUND: Psoralen photochemotherapy (PUVA), the combined use of psoralen and long wave ultraviolet (UVA) irradiation, was introduced around 1974 and its beneficial effects were rapidly confirmed worldwide. In an attempt to minimize its recognized long-term photocarcinogenic risk after some 150-200 exposures while also maintaining efficacy, however, the narrowband (311-312 nm) ultraviolet B (UVB) lamp (TL-01) was introduced in 1984, and has moved towards replacing PUVA except for severe or resistant disease. AIMS: To discover whether our use of these therapies complied with established British Photodermatology Group guidelines for PUVA and guidelines formulated within our unit for narrowband UVB. METHODS: The study was retrospective over 6 months from November 2001 to April 2002, all relevant information being obtained from the patients' hospital notes. RESULTS: Thirty-one patients received PUVA (18 oral, 11 bath and two uncertain because of missing notes) and 20 narrowband UVB during this period. CONCLUSIONS: Our PUVA and narrowband UVB phototherapy guidelines were shown to have been followed relatively closely with the following exceptions: one PUVA patient received a high cumulative exposure by mutual agreement because there was no other suitable therapy; a failure to measure minimal phototoxic doses (MPDs) in some PUVA patients; and slightly prolonged referral delays, but generally by patient choice.

Erythema multiforme following polymorphic light eruption: a report of two cases.

We report two patients in whom episodes of polymorphic light eruption were followed by recurrent erythema multiforme on exposed and nonexposed sites. Treating the polymorphic light eruption with prophylactic PUVA and/or oral prednisolone or cyclosporin prevented the development of erythema multiforme, suggesting that the two events are related. It is possible that erythema multiforme develops as a response to the same causative antigen as polymorphic light eruption.

Topical pseudocatalase mousse and narrowband UVB phototherapy is not effective for vitiligo: an open, single-centre study.

We report an open single-centre trial to assess the efficacy of topical pseudocatalase mousse applied twice daily to the hands and face of vitiligo patients, in combination with twice-weekly suberythemogenic narrowband UVB phototherapy. The regime was generally safe and well tolerated, although several patients experienced mild transient skin rashes in association with application of the mousse and one patient suffered severe pruritus. The primary efficacy variable was the percentage change in area affected by vitiligo as assessed by digital interpretation of standardized photographs of the face and hands. There was no clear evidence of the efficacy of the regime and in fact a slight tendency overall to worsening of the patients' vitiligo.

Psoralen photochemotherapy (PUVA) is only moderately effective in widespread vitiligo: a 10-year retrospective study.

A 10-year retrospective analysis of the use of psoralen photochemotherapy (PUVA) in the treatment of vitiligo was undertaken at the St John's Institute of Dermatology, London, UK. Of 97 patients included in this study, eight had complete or almost complete repigmentation, 59 moderate to extensive repigmentation, and 30 showed little or no response. However, 24 of those who had responded to PUVA with extensive repigmentation did not consider their response satisfactory because of persistence of vitiligo at cosmetically sensitive sites, and poorly matching, speckled repigmentation. Fifty-seven patients who initially improved with PUVA therapy subsequently relapsed, in most cases within a year of stopping treatment. Relapses in 22 patients were on the same cutaneous sites as previously affected, while vitiligo at new sites developed in 20 patients and both new and old sites were affected in a further 15 patients. Patients who retained their pigmentation after 2 years appeared to have a better chance of permanent remission. The only statistically significant prognostic indicator of relapse was patient age at the start of treatment, younger patients tending to retain their pigmentation longer than older patients. This study emphasizes the need for careful patient counselling before PUVA therapy as this treatment seldom achieves extensive repigmentation that is cosmetically acceptable, and treatment response is often followed by relapse.