The Collaborative International Dictionary of English v.0.48:

Papule \Pap"ule\, n.; pl. Papules.
   Same as Papula.
   [1913 Webster]

WordNet (r) 3.0 (2006):

papule
    n 1: a small inflamed elevation of skin that is nonsuppurative
         (as in chicken pox)

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "papule":
   abscess, aposteme, bed sore, blain, bleb, blister, boil, bubo,
   bulla, bunion, canker, canker sore, carbuncle, chancre, chancroid,
   chilblain, cold sore, eschar, felon, fester, festering,
   fever blister, fistula, furuncle, furunculus, gathering, gumboil,
   hemorrhoids, kibe, lesion, papula, paronychia, parulis, petechia,
   piles, pimple, pock, polyp, pustule, rising, scab, soft chancre,
   sore, stigma, sty, suppuration, swelling, tubercle, ulcer,
   ulceration, wale, welt, wheal, whelk, whitlow, wound