your symptoms are pointing toward gastroenteritis for which you should take ciplox-TZ BD for 4 days.
red rash with diarrhoea
points toward viral gastroenteritis
for which there is no specific treatment but to maintain proper hydration state by ORS intake.henoch schonlein purpura
and coeliac disease with dermatitis
herpatiformis may even present as such for which you should consult a physician so that your skin lesion can be examined thoroughly.
thanks for consulting HCM.