the features of first case were gangrene of unknown etiology , which was bilateral and simultaneous . only two cases of unilateral idiopathic lower limb gangrene in neonate are reported in literature . these two required amputation below knee . our infant recovered with debridement and amputation of gangrenous toes only . a 12-day male neonate , weighing 2.5 kg , appropriate for gestational age , born at 38 weeks to a 25-year - old primigravida mother brought to our emergency department during a winter night . there was no history of umbilical catheterization or any intravenous or intramuscular assess in baby . axillary temperature was 36.6c . left foot and toes showed purplish and black discoloration with edema [ figure 1 ] . investigations revealed a negative sepsis screen ( tlc 910/l , i : t ratio 0.12 , crp < 6mg / l initially as well as at 24 hrs of admission , micro - esr 4 mm in the 1 hour , absolute neutrophil count 2.510/l ) ; blood glucose 94 mgdl ; hematocrit 54% ; and vdrl and hiv serology were negative . the baby was negative for anticardiolipin igm and homocysteine was 10.4 mol/ l. magnetic resonance angiography was normal . intravenous antibiotics ( cefotaxim+amikacin ) were given for 14 days and dressing of the involved areas with silver sulfadiazine ointment was carried out twice daily . after 3 weeks of stay in the hospital , the baby was discharged and sent to home . the infant is under regular follow - up and is doing well at 5 months of age . . left distal foot and toes of the neonate showing blackish discoloration with edema stumps of the amputated toes are healthy on follow - up etiology is not identified in most cases and management is usually conservative with debridement and amputation of gangrenous part involving toes . it results from diminished perfusion of a part of the body , usually the extremities . known etiologies include hypercoagulable state , in uteroarterial thrombosis , polycythemia , maternal diabetes , congenital bands , birth trauma , prematurity , congenital syphilis , umbilical artery cannulation , intravenous hyperosmolar infusions and sepsis . in majority of cases , an etiological factor is not identified . upper limb gangrene is more frequent compared with that of lower limbs.[35 ] in our case , sepsis and other causes were ruled out based on investigations blister formation ( indicating superficial skin damage ) and gangrene have been described with frostbite in adults . management includes systemic antibiotics and dressing with local antibiotics so that first infection gets controlled before debridement of gangrenous part . more often , there has been progression to spontaneous slough or autoamputation or surgery and limited amputation . these two required below knee amputation and blisters in the upper limbs usually followed the gangrene . in our index case kothari et al managed four cases of lower limb gangrene in neonates , all presented with bilateral gangrene and required amputation and in two of them no cause was found . also nagai et al described the two cases of intrauterine gangrene of bilateral lower limb complicated by twin - to - twin transfusion syndrome requiring below knee amputation . in our case presentation was unilateral and amputations of toes were required . sepsis can lead to gangrene of foot but as sepsis has been ruled out in the index case we hypothesize the possibility of minor trauma leading to localized cellulitis and compartment syndrome followed by gangrene .
we are reporting a very unusual case of unilateral lower limb gangrene in 12 days neonate , who was brought to us with bluish discoloration of left foot with gangrene of toes . a negative sepsis screen , normal doppler study , normal magnetic resonance angiography and absence of evidence of hypercoagulable state prompted us to make the diagnosis of idiopathic unilateral lower limb gangrene in this newborn . 
 because of the rarity we are reporting this case with vide review of literature .