Hello dear, Thank you for your contact to health care magic. I read and understand your concern. I am Dr Arun Tank answering your concern. No, Giardia won t cause rash directly. Giardia remains limited to the intestine only. It will remain stuck to the intestine where it suck the essential nutrients particularly fat. Fat soluble vitamins are so not going to be absorb easily. The rash which had appears is because of the deficiency of the essential nutrient. So in my advice you should take the medication you are taking previously. But there is also a need to take the multivitamin tablet. This will replenish the nutrient deficient. Please adopt good hand washing practice this will make a barrier and prevent further transmission of the parasite. Please eat healthy food like food should not be dirty. This parasite also transmits with water. So drink clean and hygiene water. I will be happy to answer your further concern on bit.ly/DrArun. Thank you, Dr Arun Tank Infectious diseases specialist, HCM.