Although dollar's cross-inspired retreat from 90.08 to 88.42 suggests the erratic rise from 87.10 has formed a temporary top yesterday, a firm break below aforesaid support is needed to signal correction is under way and yield further weakness towards 87.90/00.  
On the upside, above 89.70/75 would indicate said upmove has resumed instead, bring re-test of 90.08 and later towards 90.50/60.