Rainrot: a painful and contagious skin condition in horses

Rain scurf, rainrot, or dermatophilosis is a bacterial, contagious skin condition in horses. A condition that you mainly encounter in the autumn/winter in horses during rainy periods, but can also occur in sport horses. Do you know what rainrot is and what you can do about it?

What causes rainrot in horses?

All horses have the dermatophilus bacterium on their skin, humans also have this bacterium. As long as this bacterium is on the outside of the skin, there is no problem. But as soon as the horse has a wound, the bacterium can enter and cause problems. And horses that remain wet for a long time can also have problems with this bacterium.

In horses that stand in the rain for a long time, the fat layer slowly disappears, and therefore the protection of the skin. Especially in a wet, unshorn coat, it can start to fester and this bacterium can easily multiply. But frequent washing/rinsing of the horse can also be a trigger for the development of rainrot.

What does rainrot look like?

Rainrot has characteristic points that make it recognizable:

• It starts as bumps/thickening in the skin

• Afterwards, hairs clump together and thick crusts form. These crusts eventually fall off with skin and hair.

• There is pus under the crusts, with a small skin wound beneath

• Once the crusts are gone, it resembles a skin fungus

Rainrot mainly occurs on the back, in lines where water drips off the body. In severe cases, it can also occur on other parts of the body. On the legs, it is often seen as scratches and the horse can even become lame.

The condition does not cause itching in the horse but can be very painful.

Which horses get rainrot?

The bacterium is present on almost all horses, but especially horses that are exposed to wet conditions for a long time are susceptible to developing rainrot. Also, competition horses that are frequently rinsed off lose part of their skin fat, making rainrot possible.

A weakened immune system also affects the development of the condition. Neglected horses or poor hygiene are also reasons for getting rainrot.

How to prevent rainrot?

It is important to know that rainrot is contagious. When rainrot is detected, it is important to avoid direct contact with other horses. This includes blankets, saddle pads, and other grooming equipment. Once a horse has had rainrot, it remains susceptible to the condition. For these horses, it is especially important to prevent moisture on the skin as much as possible.

Rainrot cannot always be prevented, but there are steps that can be taken to reduce the likelihood:

• Provide shelter so that the horse always has the opportunity to dry properly. Consider using blankets if necessary.

• Limit rinsing off the horse without fully drying it afterwards

• Boost the horse's immunity

How to treat rainrot?

Once rainrot is confirmed in your horse, it is important that all crusts are removed. Do not leave these crusts lying around, but immediately dispose of them in a garbage bin to prevent contamination of other horses. The skin should then be washed multiple times with a disinfecting shampoo (available through a veterinarian). It is important that the skin and coat are thoroughly dried. This can be done by taking your horse out in the sunlight or using a solarium. Finally, it is important to clean all saddle pads, blankets, and brushes thoroughly as rainrot is contagious.

If washing with an antibacterial shampoo is not sufficient, the veterinarian can prescribe an antibiotic. However, often multiple washings with an antibacterial shampoo spread out over a few weeks are sufficient.