Hi there, I would like to know how old is your baby. Is there any fever / altered behaviour as in irritability etc/ cough/ runny nose ? What is the nature of the rash - papule /pustule/ petechiae(pin point small red dots)/ vesicles ( small blisters). If any of these symptoms are present , it would be better if you take your baby to the paediatrician. If it is just a patchy reddish rash associated with itching it is most likely due to an allergic cause. You could give her anti histamines ( medication that you normally give her for cold). I cant really comment on the drug or dosage as of now , since I dont know the age/weight of the baby. Apply calamine lotion onto the area of rash. Calamine lotion application will be soothing to the child. Normally this kind of rash should go away in a day . However , if this rash is associated with any fever /excessive crying/ cough/sorethroat/altered behaviour/ if the rash persists for more than a day, please consult with a paediatrician immediately. Hope this helps. Hope your baby gets well soon :) If you have any queries , kindly get back to me .