Produced by  Herpesvirus varicellae, it is frequently observed in children, is very contagious at its onset and produces immunity.  It is an acute process which manifests with a prodromal ocurrence of headache, nasopharyngitis and general ill-feeling, preceeding a very characteristic vesicular eruption.. The vesicles contain a serous, clear liquid, which later becomes turbid, they dry up in two to three days and the center crusts over, later desquamating.  In the mouth we see papular lesions on the gingivae, palate and buccal mucosa, rupturing quickly and leaving behind superficial circular or oval erosions, which disappear without a trace. (see other photographs)