Ringworm. Sounds pretty nasty!
Actually, ringworm is not really a worm, but a fungal infection that leaves itchy, crusty, often circular, or semicircular bald spots on your dog's skin. Unfortunately, ringworm can also be transmitted to humans and other animals--it is quite contagious and is transmitted by coming into contact with the fungal spores on the hair and skin of an infected host. There are several methods of treating ringworm, including topical creams and oral medications. A medicated bath is often part of the treatment regime. However, because ringworm is contagious to humans you will want to be careful handling your infected pooch, before and during bathing and until the infection is resolved, so as not to become infected with ringworm yourself. Precautions like washing your hands, wearing gloves and long-sleeved tops, and disinfecting items your dog has come into contact with, especially towels after bathing, will be important to contain the infection and prevent yourself and other pets becoming infected.
Generally, ringworm, although unsightly and annoying, is not a dangerous infection and can be easily treated. If left untreated, however, it can spread over large parts of your dog's body and compromise the skin and hair coat. In humans, it is also generally easily treated, however, if you have an immune disorder or are undergoing treatment such as chemotherapy that impairs the immune system you should not handle or bathe a dog with ringworm, instead find someone who can bathe your dog for you.
Ringworm is usually not serious or particularly painful, or itchy, however, there can be some skin inflammation and irritation in the infected area. Infection usually results in a loss of hair and small lesions that are often in a circular pattern, thus the name ringworm--although spots may also be patchy. If the infection is left untreated and becomes widespread, inflammation and scabs can cause more severe inflammation and irritation of the skin that will cause discomfort to your dog. Occasionally, infections can affect a dog's nails, causing them to become brittle and break, which can be painful. Although your dog may be somewhat oblivious to his ringworm infection, you should not be, since it can become widespread and cause problems and it is contagious to other animals and yourself.
Ringworm is yucky, it's necessary to avoid it spreading and is time-consuming to treat and disinfect your home, but otherwise is not usually dangerous. Unless you leave it untreated and it spreads, or you or your pet are immune-compromised, dealing with ringworm is usually just an inconvenience. Take the time to prevent contamination and bathe your dog with medicated shampoos and dips, apply ointments and creams, and administer oral medication as directed to successfully eradicate ringworm. Because spores can live for several months on surfaces you will also need to thoroughly disinfect your home and dog's bedding to prevent reinfection.