A diffuse reflectance spectroscopic study of UV-induced erythematous reaction across well-defined borders in human skin.

INTRODUCTION: The colour of tissue is often of clinical use in the diagnosis of tissue homeostasis and physiological responses to various stimuli. Determining tissue colour changes and borders, however, often poses an intricate problem and visual examination, constituting clinical praxis, does not allow them to be objectively characterized or quantified. Demands for increased inter- and intra-observer reproducibility have been incentives for the introduction of objective methods and techniques for tissue colour (e.g. erythema) evaluation. The aim of the present paper was to study the border zone of a UVB-provoked erythematous response of human skin in terms of blood volume and oxygenation measured by means of diffuse reflectance spectroscopy using a commercial probe. MATERIAL AND METHODS: A provocation model, based on partial masking of irradiated skin areas, defines two erythema edges at every skin site responding to the UV irradiation. In every subject, five test sites were exposed with a constant UV light irradiance (14 mW/cm(2)), but with different exposure times (0, 3, 6, 9 and 12 s). An analysis of the spectral data measured across the two edges was performed for every scan line. The oxygenized and deoxygenized haemoglobin contents were estimated in every measurement point, using a modified Beer-Lambert model. RESULTS: The fit of the experimental data to the model derived by the modified Beer-Lambert law was excellent (R(2)>0.95). Analysing data for the chromophore content showed that the erythematous response in the provoked areas is dominated by the increase in oxyhaemoglobin. The widths for the left and right border zone were estimated to be 1.81+/-0.93 and 1.90+/-0.88 mm, respectively (mean+/-SD). The unprovoked area between the two edges was estimated to be 0.77+/-0.68 mm. CONCLUSION: While the chosen data analysis performed satisfactorily, the ability of the probe design to differentiate the spatial aspects of a reaction with abrupt borders was found to be suboptimal resulting in a probable overestimation of the erythematous edge slope. Probe modification or imaging techniques are possible solutions.

[Many travellers suffer of side-effects of malaria prophylaxis]. / Malariaprofylax ger många resenärer biverkningar.

There is still uncertainty about the frequency of side effects associated with the use of malaria prophylaxis. The biggest concern has been that of meflokin. The aim of the study was to compare different symptoms in travellers taking different prophylactic malaria drugs with a control group travelling to the same area. Travellers seeking advice at a vaccination clinic in the south of Sweden were asked to fill in questionnaires before and after returning from their travel. 303 participants returned both questionnaires, a response rate of 62%. The results showed that a greater proportion of the travellers taking malaria prophylaxis reported symptoms in comparison with that of the control group (59% vs. 41%). Also, in comparison to the control group, travellers taking chemoprophylaxis more often felt that their trip had been negatively affected by the reported symptoms. Neuropsychiatric symptoms were most common in the group taking meflokin although no significant difference between the different regimes was found. These symptoms were very rare in the control group. Gastrointestinal symptoms were most frequent in the group taking chloroquine and proguanil. A low proportion of those symptoms were connected to the chemoprofylaxis according to the travellers. Travellers taking meflokin more frequently associated their symptoms with the drug. The travellers, being most worried about taking malaria prophylaxis prior to the trip, reported symptoms more often than those not feeling any anxiety.