Lymphoma (particularly T-cell lymphoma): This condition can lead to lactic acidosis due to high cell turnover, peripheral eosinophilia as part of a paraneoplastic syndrome, and pneumonitis/pneumonia either as a direct result of the lymphoma or due to immunosuppression.

Acute Eosinophilic Pneumonia: Characterized by rapid onset of respiratory failure, often with eosinophilia and can be associated with lactic acidosis in severe cases due to tissue hypoxia.
Idiopathic Hypereosinophilic Syndrome (HES): Although more commonly associated with cardiac and gastrointestinal manifestations, HES can lead to pneumonitis and, in severe cases, lactic acidosis due to end-organ damage.
Drug-induced Eosinophilia with Systemic Symptoms (DRESS): A condition that can cause eosinophilia, pneumonitis, and in severe cases, lactic acidosis, especially if there's significant organ involvement.

Sepsis: Although not typically associated with eosinophilia, in certain cases, particularly parasitic infections, eosinophilia can occur. Sepsis is a critical diagnosis to consider due to its high mortality rate if not promptly treated.
Toxic Ingestion (e.g., Salicylate or Methanol Poisoning): These can cause lactic acidosis and, in some cases, pulmonary edema or pneumonitis. Eosinophilia might not be a primary feature but can occur as part of a systemic response.

Churg-Strauss Syndrome (Eosinophilic Granulomatosis with Polyangiitis, EGPA): A form of vasculitis that can cause asthma, eosinophilia, and systemic symptoms including pneumonitis. Lactic acidosis could occur in severe cases with significant organ involvement.
Langerhans Cell Histiocytosis (LCH): Can cause pneumonitis and, in rare cases, eosinophilia. Lactic acidosis might occur due to extensive disease or secondary infections.
Parasitic Infections (e.g., Loeffler's Syndrome): Certain parasitic infections can cause eosinophilia and pneumonitis. While lactic acidosis is less common, it could occur in severe cases with significant tissue invasion or secondary bacterial infections.