Review of 15 cases of pemphigus foliaceus in horses and a survey of the literature.
Authors: Zabel S, Mueller R S, Fieseler K V, Bettenay S V, Littlewood J D, Wagner R
Journal: The Veterinary record
Summary
# Editorial Summary: Pemphigus Foliaceus in Horses Pemphigus foliaceus is a relatively uncommon autoimmune blistering condition in horses, yet recognition and diagnosis remain challenging for practitioners unfamiliar with its presentation. Zabel and colleagues examined 15 confirmed cases diagnosed through clinical signs, histopathology and differential diagnosis exclusion to characterise the disease's epidemiology and clinical manifestations. The cohort showed no breed predisposition and wide age variability (three months to 25.5 years, mean nine years), though notably included three foals—emphasising this is not purely a geriatric condition. Scaling, crusting and alopecia dominated the clinical picture in two-thirds of cases, predominantly affecting the face, neck and trunk, with extremity involvement in nine horses; acantholytic cells were cytologically identifiable in only 67 per cent of samples, suggesting this diagnostic tool alone is insufficient. Practitioners should maintain a high index of suspicion for pemphigus foliaceus when encountering multi-site scaling and crusting lesions with minimal pruritus, recognising that negative acantholysis findings do not exclude the diagnosis and that histopathology remains essential for confirmation—particularly important given the condition's serious implications for affected horses and the need to differentiate it from other chronic dermatological conditions.
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Practical Takeaways
- •Pemphigus foliaceus should be considered in horses presenting with scaling, crusting, and alopecia on the face, neck, and trunk regardless of age
- •Cytological examination for acantholytic cells can support diagnosis in approximately two-thirds of cases and should be performed alongside histopathology
- •Clinical presentation varies widely with pain not being a consistent feature; lesion distribution and appearance are more reliable diagnostic indicators than systemic signs
Key Findings
- •Mean age of onset was 9 years (range 3 months to 25.5 years), with no apparent breed predisposition identified
- •Most frequent clinical signs were scaling (11/15), crusting (10/15), and alopecia (10/15), predominantly affecting face, neck, and trunk
- •Acantholytic cells were identified cytologically in 4 of 6 horses tested, supporting diagnostic confirmation
- •Pain was not a prominent clinical feature, contrasting with some previous reports of pemphigus foliaceus in horses