Capillary hemorrhages will appear red initially and turn brown in a few days once the extravasated red cells have lysed and have been degraded to hemosiderin. Petechiae secondary to platelet deficiencies or aggregation disorders are usually not limited to the oral mucosa but occur concomitantly on skin.
Autoimmune or idiopathic thrombocytopenic purpura (ITP), HIV-related ITP, disorders of platelet aggregation, aspirin toxicity, myelophthistic lesions, and myelosuppressive chemotherapy all will lead to purpura, with petechiae being the major lesions. Alternatively, most oral petechiae are not associated with thrombocytopenia or thrombocytopathia; rather, they are usually confined to the soft palate, where 10 to 30 petechial lesions may be seen and can be attributed to suction. Excessive suction of the soft palate against the posterior tongue is selfinflicted by many patients who have a pruritic palate at the onset of a viral or an allergic pharyngitis; they simply “click” their palate. Palatal petechiae can also appear following fellatio. When traumatic or suction petechiae are suspected, the patient should be instructed to cease whatever activity may be contributing to the presence of the lesions. By 2 weeks, the lesions should have disappeared. Failure to do so should arouse suspicion of a hemorrhagic diathesis, and a platelet count and platelet aggregation studies must be ordered.