When you notice ring-shaped rashes on the face, one of your first instincts may be to blame a ringworm infection. This fungal infection has a direct and strict course of treatment. But before you self diagnose, try to rule out other possible causes of the problem. In some cases, allergic responses to environmental contaminations can cause rashes which look suspiciously like ringworm ring rashes. An encounter with an allergenic substance on the lip of a bottle, for instance, can produce a ring-like rash. Ask questions and do some sleuthing to rule out other causes.