Hymenopteran venoms, inoculated during stings by ants, bees, and wasps, are the most frequent cause of an IgE-mediated systemic hypersensitivity reaction in adults, which is a key process in drastic manifestations of anaphylaxis. Respiratory involvement is usually caused by pulmonary edema but is rarely described as including interstitial pneumonitis or acute respiratory distress syndrome. Here, we describe a case of severe allergic reaction after a sting by Apoica pallens with late-onset pulmonary involvement, including signs of vasoplegia (pleural effusion) and interstitial pneumonitis with mild rhabdomyolysis. The presence of late onset of pulmonary involvement after a severe allergic reaction after a sting by A. pallens shows the importance of keeping a patient with severe reactions under medical care for a minimum of 5 days to avoid serious late complications outside the hospital environment.