My 19wk old has a rash- red and blotchy, slightly rough feeling. (He's very well, no scratching or temp)Haven't changed washing powder, and haven't been using soap/wipes etc. Only different thing we've done is introduce a bottle of formula every day, as we're slowly moving from breast to bottle. Could it be a lactose intolerance? (I get very minor eczema, made worse by dairy)