. ▁The ▁feet , ▁body , ▁pre pu ce ▁or ▁per ian al ▁area ▁may ▁be ▁affected . ▁P ust ular ▁ot itis ▁extern a ▁can ▁occur , ▁with ▁the ▁pin na e ▁( ear ▁f laps ) ▁becoming ▁thick ened ▁by ▁ed ema . ▁A ffect ed ▁areas ▁are ▁pain ful ▁but ▁not ▁it chy . ▁Appro xim ately ▁half ▁of ▁affected ▁pu pp ies ▁have ▁le th arg y ▁and ▁de pression . ▁Less ▁common ▁sympt oms ▁include ▁py re x ia , ▁an ore x ia , ▁and ▁joint ▁pain ▁caused ▁by ▁ster ile ▁supp ur ative ▁ar th rit is . ▁ ▁C aus es ▁ ▁The ▁cause ▁of ▁ju ven ile ▁cell ul itis ▁is ▁unknown . ▁C yt olog ic ▁exam ination ▁of ▁asp ir ates ▁of ▁affected ▁l ym ph ▁nodes , ▁p ust ules , ▁abs cess es , ▁and ▁joint ▁fluid ▁rarely ▁reve al ▁b acter ia , ▁and ▁culture ▁results ▁of ▁int act ▁les ion ▁are ▁always ▁negative ▁for ▁b acter ial ▁growth , ▁suggesting ▁a ▁non b acter ial ▁et i ology . ▁As ▁signs ▁resolve ▁following ▁treatment ▁with ▁gl uc oc ort ico ids , ▁the ▁cause ▁is ▁likely ▁to ▁be ▁an ▁imm une ▁dis order . ▁ ▁Di agn osis ▁ ▁Pu pp ies ▁are ▁first ▁presented ▁with ▁what ▁appears ▁to ▁be ▁st ap hy loc oc cal ▁py oder ma . ▁Def init ive ▁diagn osis ▁requires ▁c yt olog ic ▁and ▁hist op ath olog ic ▁evalu ations