The characteristic skin nodules and systemic signs are often sufficient during outbreaks.
· Polymerase Chain Reaction (PCR): highly specific and sensitive
· Virus Isolation: in cell cultures or embryonated chicken eggs
· Serological Tests: ELISA, virus neutralization test
· Histopathology: necrotizing dermatitis, vasculitis, and inclusion bodies
· Pseudolumpy skin disease (Bovine Herpesvirus 2): The disease may be confused with the less clinically important pseudo-lumpy skin disease, which is caused by a herpesvirus (bovine herpesvirus 2). These diseases can be similar clinically, although in some parts of the world the herpesvirus lesions seem confined to the teats and udder of cows
· Dermatophilosis
· Bovine papular stomatitis
· Photosensitization
· Insect bite hypersensitivity