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.
1 The pill will start working right away for birth control if you start on the first day of your period. 2  Start your first pack of pills on the Sunday after you start your menstrual period. 3  You should use a backup method of birth control (condoms with spermicide) until you start the pill. Use a backup method of birth control (such as condoms with spermicide) until you start the pill. 2  The pill will start working right away for birth control if you start on the first day of your period. 3  Start your first pack of pills on the Sunday after you start your menstrual period.