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.
First Day Start - Take your first pill during the first 24 hours of your menstrual cycle. No back-up contraceptive. method is needed when the pill is started the first day of your menses. Sunday Start - Wait until the first Sunday after your menstrual cycle begins to take your first pill. With this option. use another method of birth control for the first 7 days of the first cycle only. Today Start - Start the pill today.