Outcome measures used in trials have been reviewed by Finlay.25 Most outcome measures have incorporated some measure of itch, as assessed by a doctor at periodic reviews or patient self-completed diaries. Other more sophisticated methods of objectively recording itch have been tried. Finlay drew attention to the profusion of composite scales used in evaluating atopic eczema outcomes. These usually incorporate measures of the extent of atopic eczema and several physical signs such as redness, scratch marks, thickening of the skin, scaling and dryness. Such signs are typically mixed with symptoms of sleep loss and itching, and variable weighting systems are used. It has been shown that measuring surface area involvement in atopic eczema is fraught with difficulty,26 which is not surprising considering that eczema is, by definition, "poorly defined erythema". Charman et al. performed a systematic review of named outcome measure scales for atopic eczema and found that of the 13 named scales in current use, only one (SCORAD) had been fully tested for validity, repeatability and responsiveness.27 Quality-of-life measures specific to dermatology include the Dermatology Quality of Life Index28 and SKINDEX.29 The Children's Dermatology Life Quality Index has been used in atopic eczema trials in children.
Most clinical trials of atopic eczema have been very short (i.e. about 6 weeks), which seems inappropriate in a chronic relapsing condition. Few studies have considered measuring number and duration of disease-free periods. In the absence of such long-term studies it is impossible to say whether modern treatments have increased chronicity at the expense of short-term control.
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