What is "alergico"

"Alérgico" is a song by Mexican singer Anahí released on October 19, 2010. The song is included and taken of the re-release album of Mi Delirio (2009) released as the fourth single. Three versions of the song were recorded, the album version with Anahí only, the Portuguese version featuring Brazilian singer Renne Fernandes (from Hevo84), included on the Edición Deluxe (Brazilian edition) from the album, on a duet version featuring Argentinian singer-songwriter Noel Schajris, released digitally on January 11, 2011, and included on the Edición Deluxe (Colombian edition) from the album. The song is considered her most successful single from the album in Mexico, since reached number 2 on the main airplay chart, as well the strong sales in digital marketplaces.