Ringworm (dermatophytoses)

Ringworm is a fungal infection.  There is no worm.  Ringworm derives its name from the ring that forms from the fungal infection as it starts at one source and slowly grows outwards.

Can my family or I get ringworm?

Ringworm is a zoonotic disease.  This means, ringworm can infect dogs, cats, and humans.  If you suspect your pet has ringworm, have him evaluated with your family veterinarian.

What is ringworm?

There are multiple types of fungi that causes ringworm infections including microsporum and trichophyton.  If there is an analogous disorder to relate ringworm to, it is athlete's foot. 

Ringworm (dermatophytes) are normal inhabitants in the environment.  They live in moist areas as ringworm is sensitive to drying and heat.   Here in Southern California, there are "blooms" of ringworm that occur when the season allows.  Late summer to early fall have a flurry of cases that present to veterinarians. 

How is ringworm diagnosed?

Ringworm present as focal areas of loss of hair.  These areas range in size from 1/2 inch in diameter to two inches in diameter.  There may or may not be a ring of redness or inflammation.  Ringworm can affect any area of skin but lesions often occur on the head, ears, lower legs, or groin region. 

Diagnosing ringworm can be a long (up to two week process).  There is one species of ringworm that can fluoresce with a Wood's lamp.  The appearance of the skin lesion, history, and confirmatory tests including Wood's or a DTM (Dermatophyte Test Medium) fungal culture may be performed by your veterinarian.

How is ringworm treated?

Treatment of ringworm requires treatment of the environment and treatment of your pet.  If the environment is not treated, you or your pet may get infected or re-infected as there is no immunity to ringworm.  Treatment of your pet is required to prevent further contamination of the environment.  Treatment of the environment is more challenging and equally as important as treatment of your pet. 

Dermatophyte (Ringworm) Sanitation

Protective items (latex or nitrile gloves, cleaning type clothing) should be worn. 

It is recommended to clean all contaminated surfaces of infected hair.  For smooth surfaces, use electrostatic cleaners (e.g. Swiffers).  Vacuum furniture, rugs, and carpets daily for one week.

After vacuuming, if the non porous surface allows, disinfect with a 1:10 bleach solution (1.5cups of bleach in 1 gallon of COLD tap water).  Warning - this solution will stain clothes, fabrics, and some colored surfaces.   Bleach solution should be applied wet, allowed to sit for 10 minutes, then wiped clean with wash cloth moistened with water.  This should be performed a total of two times.

Vacuum both the intake and exhaust air conditioning and heating vents. 

If there is significant carpet or rugs, hire a professional steam cleaning surface.  Ringworm will be destroyed by heating to above 110 degrees Fahrenheit.  Most rental units even filled with hot water cannot achieve this temperature at the point of contact.

Bedding, toys, animal clothes, brushes should be discarded and replaced. 

Treatment of your pet

There are both topical and oral treatments available for animals.  Type of treatment will depend on number of lesions present, severity of lesions, and environmental concerns.  Due to the zoonotic potential, speak with your family veterinarian to implement an effective treatment protocol as soon as possible.



Written January 6, 2015 by JKim