WordNet (r) 3.0 (2006):

hypersensitive
    adj 1: having an allergy or peculiar or excessive susceptibility
           (especially to a specific factor); "allergic children";
           "hypersensitive to pollen" [syn: allergic,
           hypersensitive, hypersensitized, hypersensitised,
           sensitized, sensitised, supersensitive,
           supersensitized, supersensitised]

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "hypersensitive":
   allergic, anaphylactic, delicate, empathetic, empathic, goosy,
   hairsplitting, high-strung, hypercritical, hyperesthetic,
   hyperpathic, irritable, itchy, miffy, morbidly sensitive, nervous,
   overconscientious, overcritical, overfastidious, overmeticulous,
   overnice, overparticular, overprecise, overrefined, overscrupulous,
   oversensible, oversensitive, oversqueamish, overtender, passible,
   prickly, refined, responsive, sensitive, skittish, supersensitive,
   sympathetic, tactful, temperamental, tender, tetchy, thin-skinned,
   ticklish, touchy, ultracritical