Ringworm, not really a worm, is an infection of hair follicles

At the mention of ringworm, we think of a little worm that causes itchy circles in our skin and scalp.  

Ringworm infections, however, are not caused by worms and often do not follow any particular pattern in their appearance.

 Ringworm infection is very common in dogs and cats. It may be caused by any of three different fungal species that colonize the lining of the hair follicles (the pores in the skin that the hair roots set in). The fungus causes the hair root to loosen in the follicle and the hair comes out.

 The fungus may cause far more than just hair loss.  The skin may react to the presence of this invader by swelling and by discharging serum. If this occurs, we see raw red areas and the animal may sometimes chew or scratch at them.  This damages the skin further and allows secondary bacterial infection to begin.

Ringworm infection is very common in dogs and cats. It may be caused by any of three different fungal species that colonize the lining of the hair follicles.

The appearance of ringworm can vary from a classic circular, scaly, hairless area to pinpoint patches of scabbiness or large open red sores. Thus, ringworm can mimic many of the skin conditions that animals are susceptible to.

 Positive diagnosis of ringworm in the dog or cat can be made only by laboratory testing of the fungal elements in the hair.  Diagnosis is important since some types of ringworm are transmissible to humans. All of the common types may be transmissible to other dogs or cats. Even laboratory diagnosis of ringworm is often elusive since the fungus does not always grow under artificial conditions.

 Successful treatment of ringworm in the animal can be difficult to achieve.  Animals may often be on topical or oral treatments for long periods of time only to have the infection show up again. Fungi are hardier organisms than we would like them to be.

(Dr. Fred Conkel is a veterinarian who owns Westgate Clinic.)