Particular onset of Sars-Cov-2 infection, by acute mastoiditis without symptoms specific to the case definition. Mastoiditis is part of inflammatory diseases of the middle ear and is important because of its frequency and life-threatening complications due to the close relationship between the middle ear and the cranial cavity. An acute middle ear inflammation may follow a serious course even if the tympanic membrane does not perforate. In the pathogenesis of acute suppurations of the middle ear, the Eustachian tube plays a major role in the appearance of inflammation and the development of the disease. The most common germ can be - a virus whose initial effect is congestion of mucosa and reduce resistance to biological defence by promoting rapid superinfection with Hemophilus Pneumococcus, Staphylococcus, and others. Sars-Cov-2 infection begins with respiratory phenomena and clinical and biological inflammatory syndrome. This article presents a case of Sars-Cov-2 infection with atypical onset of acute mastoiditis. The clinical importance lies in the fact that the virus can migrate from the nose and nasopharynx through its Eustachian tube into the middle ear and from here to the mastoid. The presence of the virus in the middle ear is almost constant even if the patient is asymptomatic. This requires precautions in all surgical maneuvers at this level in patients with Sars-Cov-2 infection.