Ringworm is an infection on the surface of the skin that is caused by a fungus. It is common in children but can also occur in adults. It is usually passed by direct skin contact with another person who has ringworm or by touching a contaminated surface such as dirty clothing or towels. You may also be able to get the infection from household pets or contaminated soil.
This skin condition often looks like many tiny pink bumps connected in the shape of a ring or a worm. There is no actual worm in the skin, however. The infection may start out as a small spot that spreads outward and grows wider, up to an inch or two, often leaving a clear or less bumpy center. The skin lesion may be scaly or fluid-filled and may itch or feel painful.
The diagnosis of ringworm may be made by a physician who looks at and identifies the skin lesion. Some lesions may not appear typical of ringworm so other tests may be needed. For example, a special purplish light called a Wood's lamp may help confirm the diagnosis of ringworm; in a dark room, some fungi will appear to glow under this lamp. Your doctor can also gently scrape the infected skin to see whether it contains fungus.
Ringworm infections typically go away after applying an anti-fungal cream for about four weeks. If your child's infection has not gone away after a month of using the cream, it's possible that the medication is not correct for her condition or that she may need a stronger anti-fungal product such as a prescription-strength ointment or cream, or an oral anti-fungal medicine. Also, certain medications, such as steroid creams, may make the ringworm worse so if your daughter is using a combination anti-fungal/steroid product, a plain anti-fungal cream will likely work better.
On the other hand, ringworm may look similar to other skin conditions such as eczema, which can occur in round patches that look like rough coins called nummular eczema. The treatment for these conditions will be different from ringworm medications, so it's important to let your doctor know that the current medication is not working. Good luck!