Pegasus snatched the consumer brief from incumbent Frank PR following a three-way pitch.
The four-day show, which will take place at Earls Court from 24 to 27 March, attracts more than 40,000 female visitors and showcases more than 300 health, beauty and wellbeing brands, including Benefit, Bio-Oil and Pom Wonderful, the 100 per cent pomegranate juice drink.
Sussex-based Pegasus will manage all consumer media relations, drive the sales of tickets, 'Pamper Packages' and new 'Taste Packages', in addition to Vitality Workshops.
The agency will aim to strengthen the event's reputation as the UK's leading consumer show for women and position the event as 'the ultimate girls' day out'.
The brief begins immediately and runs to 1 April.
A number of Pegasus' clients will be exhibiting at the show, including natural health and skincare products, Comvita and healthcare supplement specialist BioCare, with more set to confirm in the coming months.
Helen Yeardsley, board director at Pegasus, said: 'With so many of the experts we deal with on a day to day basis speaking at the event and clients exhibiting, we will be able to add value to all the show's key stakeholders.'
The Vitality Show is set to expand its offering at next year's event, with additional areas including a large dance arena, Pom Wonderful kitchen and fashion arena.