Several infectious skin diseases also cause a rash. These can be caused by a number of infections with bacteria or viruses, and infestations of mites within the skin. Some infectious skin diseases, such as scabies, are caused by mites that bore into the skin surface causing irritation and a localised rash.
Now, as for your question about when to start taking oral contraceptives, there's really no hard-and-fast rule about when to start taking birth control pills. Starting in the first few days of your cycle is the surest way to prevent inadvertently taking pills while you are pregnant.
(Check with your health care provider if youâre not sure which kind of pill youâre taking.) So thereâs no need to ever wait for the first day of your period to start taking birth control pills â you can start whenever you like! At the longest, youâll only have to wait seven days for the pills to start being effective.