Thunderstorm-related asthma is a dramatic example of the allergenic potential of pollen antigens. Pollen allergic patients who encounter the allergenic cloud of pollen during a thunderstorm are at higher risk of having an asthma attack. Relapse is also possible and we describe here the first case of relapse of near fatal thunderstorm-asthma occurred in a 36 years old, 20 weeks pregnant woman affected by seasonal asthma and sensitized to allergens released by Parietariapollen. Patients suffering from pollen allergy should be alerted of the danger of being outdoors during a thunderstorm in the pollen season and if they experienced an episode of severe thunderstorm-related asthma could be at risk of a relapse during a heavy precipitation event.