Haemophilus paragallinarum (H. paragallinarum) or Avibacterium paragallinarum (A. paragallinarum) is a Gram-negative bacterium causing infectious coryza (IC) in chickens. Infectious coryza is an acute upper respiratory infection that causes significant economic and productivity losses worldwide. Despite the use of prophylactic measures and treatment, the infection persists due to antibiotic resistance and a superior advantage in its outer protective antigen, resulting in a complicated disease pattern. Definitive diagnosis of the disease is hindered due to major challenges that are related to the complicated bacteriological isolation of the bacterium, which could be isolated only during the acute stage of infection, in addition to the fastidious and slow growth pattern of the organism. Egypt, as a key supporter of the chicken sector, is constantly threatened by this insidious infection, necessitating the development of new technology to combat it. The significance of A. paragallinarum infection, the prevalence of serotypes, clinical signs, characterization, diagnostic tools, prophylactic approaches, and therapies are discussed in this review. This article aims to provide more knowledge about the disease organism, newer diagnostic and therapeutic techniques for efficient containment of the organism therefore reducing the disease's negative economic impact.