IntroductionBuerger’s disease usually presents with normal blood tests. We present a case with significant eosinophilia, a phenomenon rarely reported. Eosinophilia with acute onset Raynaud’s and critical ischemia can be atypical early manifestation of Buerger’s disease (thromboangiitis obliterans).Case descriptionA case report of a 24-year-old male, smoker, with no other history, presented acutely, complaining of cool, painful hands with tricolour changes with worsening for 48 hours. On examination, apart from features of Raynaud’s and tender fingers, he had good perfusion, as shown by Doppler testing. Blood tests showed eosinophilia; 13x10*9 (Normal 0.04-0.40 x10*9) and mild raised C-reactive protein 24 (normal range <10.0 mg/L). Chest radiograph, ECG, and echocardiography showed no abnormalities. The results of initial screening including Immunoglobulins, complements, ANA, ANCA, RF, APLA and CCP were all negative. As there were no critical features of ischemia, we considered the patient for discharge from the hospital with a plan for close review. We strongly advised him not to smoke. He re-admitted within a week with worsening of Raynaud’s and features of critical ischemia with bluish nail and fingertip and some early features of mild digital necrosis. We began treatment with intravenous heparin, aspirin, and iloprost (prostacyclin) infusion for 10 days. The patient’s digital ischemia and intermittent claudication showed some improvement after 1 week, but eosinophilia persisted at 11x10*9 with ruminant pain in digits. The importance of smoking cessation was re-emphasised. Magnetic resonance angiography showed no occlusion of the distal arteries of the upper and lower extremities. Capillaroscopy showed micro haemorrhages (no connective tissue disease/scleroderma pattern abnormality). Investigations for parasitic infections and malignancy were negative. HIV / Hepatitis B/C CMV/EBV/Parvovirus IGM was all undetected. Schistosoma testing was negative. Haematology investigated him for the rare possibility of the genetic mutation for hypereosinophilic syndrome (PDGFRA and FIP1L1 genes) which was negative and underwent bone marrow biopsy which was also normal.We started him on oral prednisolone 1 mg/kg body weight with complete resolution of eosinophilia and ischemic symptoms plus Raynaud’s. Smoking stopped with help.DiscussionBuerger’s disease is a rare disease of exclusion and recognised as one form of vasculitis with a strong association with smoking and nicotine. There has been no consensus or any significant data for any specific therapies proven a benefit in this condition, more than in alone stopping smoking or even oral tobacco products. The main characteristic features of this form are present in young smokers with no systemic disease manifestation, normal inflammatory response, and negative immunology.Eosinophilia has only rarely been a feature of the presentation of Buerger’s disease. Its presence does not imply a systemic vasculitis or a related syndrome. Although there is limited evidence for the use of steroids in this condition, inflammatory features such as eosinophilia could strengthen the rationale for using steroids in certain cases by halting the ongoing immune driven inflammatory cascade. The presence of eosinophilia might suggest alternative pathogenic mechanisms in certain cases of Buerger’s.Key learning pointsTo recognise eosinophilia as a marker in atypical Buerger’s disease presentation. Being a disease of exclusion we have to rule out all other possibilities including some rare ones as was done in this case by seeking advice from infectious disease and haematology team.Conflicts of interestThe authors have declared no conflicts of interest.