Highlights of recent clinically relevant papers

Treatment of summer eczema R. Hallamaa and colleagues in Finland have reported the findings of their clinical study analysing the phospholipid content of autogenous serum preparations used to treat equine summer eczema. Insect bite hypersensitivity (summer eczema) is a common cause of pruritus and skin lesions in horses; recently oral administration of diluted autologous serum has been advocated as a treatment option. The reason for this is the belief that affected horses overproduce lipids which form aggregate complexes and interrupt cell signalling, and by preparing autoserum with water and ethanol it is believed that these complexes are dissolved and the bioavailability of these lipids is therefore improved. This study assessed the phospholipid content of these autoserum preparations derived from both clinically affected and normal horses. Serum was collected from 16 horses, of which 10 were clinically affected by summer eczema and 6 were healthy controls. The duration of clinical signs varied from 2 months to 4 years and all horses had been withheld from treatment with corticosteroids or antihistamines for a minimum of 2 weeks prior to commencing the study. Autoserum was prepared as previously described and lipid analysis was performed using mass spectrometry, with subsequent quantitative analysis. Within the affected group there was a significantly greater concentration of phosphatidylcholine and sphingomyelin compared to the control group, which may be relevant in the observation that some horses with this disease respond favourably to autoserum therapy. The authors concluded that horses with insect bite hypersensitivity have a higher concentration of some specific phospholipids than normal horses; further investigation is required to establish the role of autoserum therapy in the treatment of insect bite hypersensitivity.