Field treatment of facial and scalp actinic keratoses with photodynamic therapy: survey of patient perceptions of treatment satisfaction and outcomes.

BACKGROUND: Diffuse field change with actinic keratoses (AK) is a ubiquitous skin disease in Australia, with potential for malignant transformation. We report on 35 consecutive patients who had field therapy with single session photodynamic therapy (PDT) using 1 h incubation time for 5-aminolevulinic acid (5-ALA) or 3 h for methyl-aminolevulinate (MAL). METHODS: We retrospectively telephone surveyed our patient cohort regarding their satisfaction and perceptions of the effectiveness, side-effect profile and benefits of PDT. We also reviewed all patients' notes for significant side-effects. RESULTS: Sixty-nine per cent (n = 24/35) of patients responded to the telephone survey; 66% (n = 16/24) of the respondents reported good clearance of AK and claimed a good cosmetic outcome. All respondents reported moderate or severe pain (42% and 58%, respectively) during the illumination phase. Twenty per cent of all patients treated had suffered from one or more of the following side-effects: pustulation; severe erythema; and skin erosions. CONCLUSIONS: Overall, our results compared favourably with previously published studies using 5-ALA or MAL PDT. However, our patient cohort experienced a greater side-effect profile. This may have been due to our patients having greater disease burden compared to other studies and possibly due to our use of topical retinoids prior to PDT in selected patients.

Potential photocarcinogenic effects of nanoparticle sunscreens.

Titanium dioxide and zinc oxide nanoparticles are being increasingly formulated in sunscreens. While the same compounds, in larger particle form, work by reflecting UV radiation, in nanoparticle form, they absorb UV radiation, resulting in photocatalysis, releasing reactive oxygen species. These reactive oxygen species are known to have the capability to alter DNA. Previous studies suggest that this photocatalytic process may not be significant, because the nanoparticles do not penetrate below the level of the stratum corneum. However, some recent studies suggest that nanoparticles may, under certain circumstances, breach that barrier. The majority of those studies have used animal skin models rather than human skin.