The efficacy of imiquimod 5% cream (Aldara® in the treatment of aural plaque in horses: a pilot open-label clinical trial.

This study explores the use of imiquimod 5% cream in treating aural plaques, which are linked to papilloma virus, in horses. Results showed the treatment was effective with minimal recurrence of the lesions after treatment, but caused local inflammation and discomfort at the site of application.

Background and Objective

• The research was aimed at exploring the effectiveness of imiquimod 5% cream in treating aural plaques in horses. Aural plaques are an equine skin condition associated with the papilloma virus, affecting at least 22% of horses. Some horses show no symptoms while others present ear sensitivity.
• The scientists decided to investigate imiquimod 5% cream because it has antiviral properties and modifies the immune response, which they hoped would be effective against this virus-associated condition.

Methodology

• The study enrolled 21 horses, of which 16 completed the study. The treatment entailed applying the cream three times a week, every other week.
• When both ears of a horse were affected, the researchers treated only the ear in worse condition. They recorded any adverse effects noted, such as inflammation, exudation, or thick crust formation around the treatment site.
• Removing the crust before treatment was necessary, but it was painful for the horses and most required sedation.

Results

• All horses experienced complete lesion resolution immediately following treatment. The long-term resolution rate – presumably some time after stopping the treatment – was 87.5%.
• The treatment period varied between horses, ranging from 1.5 to 8 months (the median duration was 2.9 months, and average was 3.5 months).
• A follow-up was conducted 12 to 22 months after treatment cessation, during which two horses had a recurrence of lesions.
• Before the treatment, 11 of the 16 horses (68.8%) displayed signs of disturbance such as resistance to ear touching or bridling. However, all these signs resolved completely in the horses that were followed up for at least 12 months.

Conclusion

• The study concluded that the application of imiquimod 5% cream is a viable treatment for aural plaques in horses.
• Though there was evidence of adverse effects at the treatment site, such as inflammation and discomfort, the treatment showed significant effectiveness in lesion resolution and minimal long-term recurrence.