Condition presumably suffered by Little Miss Muffet (13)
I believe the answer is:
arachnophobia
(Other definitions for arachnophobia that I've seen before include "A particular morbid fear - aha! a brooch pin (anag)" , "Miss Muffet's complaint?" , "Morbid fear of spiders" , "Abnormal fear of spiders" , "Creep-crawly fear" .)