Irritating pests - parasitic skin diseases in horses

A horse’s skin – being its largest organ – reflects its state of health. Changes to the skin may be due to ectoparasites, parasites that nest in the coat or the skin.

Ectoparasites that attack equine skin include Trichodectidae, or chewing lice. The horse louse (Werneckiella equi) has a length of approximately 1.4 - 1.8 mm and on close examination can even be seen with the naked eye. Often one can also recognize the whitish pear-shaped eggs, about 0.8 - 1.2 mm in size, which stick to the horse’s hair. Chewing lice infestations occurs mainly in autumn and winter, when the horses are stabled. Chewing lice like to move around and bite the skin, causing itching, restlessness and bald spots.

Less often, horses are attacked by other types of lice. A massive lice infestation can lead to anaemia, but symptoms are usually limited to itching, general restlessness, hair loss and scabs in the affected areas. Depending on the type, lice can be between 2.0 and 3.8 mm in size.

Skin changes caused by mites are called mange. Mange in horses can be caused by three types of mites:    
  • Sarcoptes equi (a species of mites) cause what’s known as sarcoptic mange, which usually begins at the head and withers and then spreads to the neck, shoulder and saddle area. Conspicuous are skin changes in the form of bumps, cysts or scabs, which may be accompanied by itching, hair loss or wrinkles.    
  • Psoroptic mange is caused by the Psoroptes mite (Psoroptes equi). Typical body areas susceptible to infestation from Psoroptes mite are the throatlatch, inside hindquarters and base of the mane or tail. Here, too, skin changes such as bumps, scabs, rashes, thickened skin, hair loss or itching can occur.
  • The mange mite known as Chorioptes equi causes the so-called chorioptic mange. This mite sits mainly on the skin at the back of the pastern. Often horse breeds with long feathering are affected. Chorioptic mange can lead to cracked heel and thus to scab formation. After loss of the upper skin layers, the affected areas usually begin to wet. Also typical for this form of mange is severe itching, mostly at night.
Less often horses are affected by demodicosis caused by mites at the hair follicles. The female mites penetrate the skin to deposit their eggs in the area of the hair follicles or the sebaceous glands of the eyelids. A demodicosis infestation leads to the formation of bumps and bald spots. The main areas affected are the head, shoulder, saddle and breast areas.

Which horses are affected?
Older and sick horses with a weak immune system in particular, but also horses that suffer from stress or are not sufficiently supplied with the necessary minerals and trace elements are susceptible to these plagues.

How can it be prevented?
Regular care of the horse and proper stable hygiene are essential. Each horse, therefore, should have its own grooming kit in order to prevent the transmission of parasites.

Generally it is important to always consult your vet about any skin changes. A veterinarian can make the correct diagnosis through a clinical examination, sometimes through a hair or skin sample, and prescribe the appropriate treatment.

Recommended feeding:
Special herbs can assist in prevention and recovery. For example, Bergsiegel Rose Hip Powder helps strengthen your horse's immune system due to its high vitamin content. Bergsiegel Nigella Seeds help wounds to heal faster, strengthen the immune system and help heal skin problems and eczema.

Since the liver and kidneys have the important function of detoxifying the body, supporting the horse's metabolism through liver and kidney detoxification can help fight a parasite infestation. This can be done through the proven herbal mixture in Bergsiegel Herbs for the Liver and Bergsiegel Herbs for the Kidneys.

An inadequate supply of minerals and trace elements can weaken the immune system, increasing the horse’s susceptibility to skin parasites. Naturmineral, Seniormineral for older horses and Weidemineral Cobs (especially for the grazing period) all provide your horse with important minerals and vitamins. A zinc deficiency can cause wounds to delay in healing. A zinc deficiency can be compensated with Zink Pur.

AlpenGrün Mash is rich in vital substances. It promotes equine digestion and also provides a healthy skin and beautiful coat.AlpenGrün Müsli is also suitable as a natural, healthy supplement for sensitive horses.

Dr. med. vet. Katharina Boes
June 2015  ©AGROBS GmbH
  • Dietz O., Huskamp B.: Handbuch Pferdekrankheiten. Enke Verlag Stuttgart, 2006 

(* The references refer to the technical content of the text and not to the product recommendations.)