Ringworm causes a ring-shaped rash, but it is definitely not a live worm crawling under the skin. Instead, it’s a fungus-like organism that causes a limited circular, scaly lesion with an even scalier edge. The lesion usually grows slowly to no more than a few inches in diameter. The discomfort is minor and external: a slight itching. Ringworm can sometimes be confused with simple dryness of the skin. It is mildly contagious; kids scratch the lesions and then contaminate their friends by touching them with fingers that harbor the fungus under the nails. Ringworm can also be acquired from dogs and cats that go outside. Adults rarely contract it.
Because it’s called a worm, this ring-shaped lesion raises more concern than it warrants. It may heal on its own within a few weeks, even without treatment, but upon diagnosis, you can apply an antifungal cream such as Lotrimin, which speeds up the disappearance.
In the northeastern regions of the United States, where Lyme disease is endemic the ringworm rash can be mistaken for Lyme’s characteristic “bulls-eye” lesion [See: Lyme Disease]. If you have any question about what you’re looking at, ask your doctor.