Thromboangiitis obliterans (TAO), also known as Buerger disease, is an inflammatory, nonatherosclerotic, vasoocclusive disease affecting small and medium-sized vessels of the extremities. TAO most commonly affects adult males with a significant history of tobacco consumption (e.g., smoking, chewing, vaping). In susceptible individuals, tobacco exposure causes inflammation of the , with the formation of a highly cellular thrombus that occludes the affected vessel. Patients frequently present with intermittent claudication, Raynaud phenomenon, and migratory superficial thrombophlebitis. Eventually, critical limb ischemia develops and the patient presents with rest pain, absent pulse in the extremities, and/or digital ulcerations. Angiography can determine the extent of the disease and differentiate TAO from other causes of peripheral vasculopathy. The most important therapeutic measure is the complete avoidance of tobacco exposure. Additionally, prostaglandin analogues (e.g., iloprost) may be used to improve ulcer healing and decrease rest pain. Patients with TAO who develop gangrene require amputation.
TAO is an inflammatory, nonatherosclerotic, vasoocclusive disease affecting small and medium-sized vessels of the extremities.
Histopathological phases 
- Acute phase
- Intermediate (subacute) phase
- Chronic phase
TAO affects the small and medium vessels of the extremities. Other systems are only very rarely involved.
- Migratory superficial thrombophlebitis (recurrent): often seen prior to the onset of limb ischemia ; 
- Raynaud phenomenon
- Chronic or acute limb ischemia: may progress from distal to proximal vessels
TAO typically affects more than one limb. 
Systemic symptoms 
TAO is a clinical diagnosis that requires:
- Typical clinical features in a patient with a history of tobacco consumption
- Exclusion of differential diagnoses of TAO
- Imaging studies (i.e., angiography and echocardiography) can be obtained to rule out other embolic sources and support the diagnosis.
- A biopsy may be indicated in patients with atypical presentations.
- Consultation with vascular surgery and/or rheumatology is often required.
Laboratory studies 
The following studies are normal in patients with TAO and should be obtained in all patients to rule out alternative diagnoses:
- Liver studies
- ESR and CRP
- Autoantibodies (e.g., , , anticentromere antibodies)
- Coagulation studies (see “Hypercoagulable states”)
Imaging studies 
- Echocardiography: indicated in patients with a suspected cardiac source of emboli
- : may be decreased 
- Additional laboratory studies: Consider based on the patient's clinical features (e.g., urine drug screen, serum cryoglobulins). 
- There is no specific treatment for TAO.
- Tobacco abstinence is the most important therapeutic measure.
- Pharmacotherapy may improve ulcer healing.
- Revascularization procedures are rarely performed.
- Consult a vascular surgeon and/or a rheumatologist for all patients.
Prevention and supportive care 
- Abstinence from tobacco in any form (e.g., smoking or chewing tobacco, nicotine patches or gum)
- Most effective measure for reducing symptoms
- Decreases the risk of amputation if started early in the disease course
- Protection of fingers and toes from cold and mechanical injuries (e.g., wearing gloves and appropriate footwear)
- Basic wound and skin hygiene (e.g., cleaning with soap and water, covering wounds with clean bandages) contributes to ulcer healing and prevents infections. 
Complete cessation of tobacco consumption in any form is the single most effective therapeutic measure. 
Symptomatic therapy 
- Calcium channel blockers (nifedipine, amlodipine): commonly prescribed, but evidence of effectiveness is lacking 
- Iloprost improves resolution of trophic changes and may reduce the amputation rate.