Hereditary equine regional dermal asthenia in two Quarter horses in Austria.

Summary Hereditary equine regional dermal asthenia (HERDA) is a skin disease with changes of the collagen fibres in Quarter horses. The mode of inheritance is autosomal recessive. Affected horses suffer from hyperextensible skin that is easily torn and results in badly healing wounds and atrophic scars. The skin lesions are usually located on the dorsum and rarely on the neck or the extremities. The disease typically starts in the first 2 years of life and has been reported in North America, Brazil and England. The diagnosis is based on the clinical skin lesions and the histopathologic changes of skin biopsies. Furthermore ancestors known to be HERDA-carriers increase the suspicion. A genetic test has recently been developed which allows the detection of heterozygous carriers and homozygous affected horses easily by analysis of DNA in the hair bulb. This case report describes HERDA diagnosed in 2 Quarter horses in Austria for the first time.