Horse allergy: Not only Curly Horses offer a chance for horse allergic riders. An observational study with 103 equine allergic riders and a genetic and immunological study on Curly Horses and non Curly Horses

The aim of the first study was to observe clinical horse-allergic riders during contact to Curly Horses, to detect the reason for the curliness and to determine the supposed hypoallergenicity.103 horse allergic riders, who had given up riding because of allergic symptoms during contact to horses, have been investigated for allergic reactions to Curly Horses during contact. We measured lung function as well as peak nasal inspiratory flow before, during and after 1312 riding hours and 300 horse grooming units. To examine the differences between Curly Horses and non Curly horses, we determined genetic and allergological characteristics of the used Curly Horses and Non Curly horses. Regarding the results of allergen liberation investigation we tested horse allergic riders on non Curly Horses with similar allergen release as found in Curly Horses. – The results of 4918 spirometric and 4689 measurements of nose function, never showed a relevant reaction of the lung function or nasal flow in 92 out of the103 patients due to riding or grooming the Curly Horses. For the remaining 11 patients an initial significant decrease of FEV1 was observed in first riding hours or first grooming units. A regular contact with these horses removed the mild allergic reactions of the start period of contact. The used Curly Horses were tested positive for curliness by KRT25 or SP6 mutation, the non-Curly horses were negative. In immunoblots no differences between Curly and non-Curly horses were found. The allergen content of the measurable allergens in Curly fur did not differ significantly from non-Curly Horses. During riding, the allergen release of Equ c1 and Equ c4 of the tested Curly Horses was mainly low or equal compared with two non-Curly horses while two further non-Curly horses had significantly higher scores. However, riding on two non-Curly horses with similar Equ c1 release results as in Curly horses indicated borderline lung function reactions in some tested riders, in contrast to no allergic reaction in riding Curly Horses on the same day Long term use of Curly horses induced a loss of allergic reactions to them. It seems possible that other horses with lower allergen release can be used also in this way. Compared to the other horses tested, the Curly Horses tested were not exclusively hypoallergenic.