uro im aging ▁and ▁lab ▁tests . ▁ ▁In ▁general , ▁people ▁compla ining ▁of ▁their ▁" first " ▁or ▁" wor st " ▁head ache ▁war rant ▁imag ing ▁and ▁further ▁work up . ▁People ▁with ▁progress ively ▁w ors ening ▁head ache ▁also ▁war rant ▁imag ing , ▁as ▁they ▁may ▁have ▁a ▁mass ▁or ▁a ▁ble ed ▁that ▁is ▁gradually ▁growing , ▁pressing ▁on ▁surrounding ▁structures ▁and ▁causing ▁w ors ening ▁pain . ▁People ▁with ▁ne uro log ical ▁find ings ▁on ▁exam , ▁such ▁as ▁weak ness , ▁also ▁need ▁further ▁work up . ▁ ▁The ▁American ▁Head ache ▁Society ▁recomm ends ▁using ▁" SS NO OP ", ▁a ▁m nem onic ▁to ▁remember ▁the ▁red ▁flags ▁for ▁ident ifying ▁a ▁secondary ▁head ache : ▁ ▁System ic ▁sympt oms ▁( f ever ▁or ▁weight ▁loss ) ▁ ▁System ic ▁disease ▁( H IV ▁in fection , ▁m align ancy ) ▁ ▁Ne uro logic ▁sympt oms ▁or ▁signs ▁ ▁On set ▁sudden ▁( th under c lap ▁head ache ) ▁ ▁On set ▁after ▁age ▁ 4 0 ▁years ▁ ▁Pre vious ▁head ache ▁history ▁( first , ▁worst , ▁or ▁different ▁head ache ) ▁ ▁Other ▁red ▁flag ▁sympt oms ▁include : ▁ ▁Old ▁head aches ▁ ▁Old ▁head aches ▁are ▁usually ▁primary ▁head aches ▁and ▁are ▁not ▁dangerous . ▁They ▁are ▁most ▁often ▁caused ▁by ▁mig ra ines ▁or ▁t ension ▁head aches . ▁Mig ra ines ▁are ▁often ▁un il ater al , ▁pul sing