A 17–year–old male presented with a three–day history of shortness of breath, non–productive dry cough, pleuritic chest pain, and fatigue. He had recently recovered from infectious mononucleosis. He was hypoxic with an oxygen saturation of 92% on room air and a chest x–ray was consistent with multilobar pneumonia. The patient was admitted and treated with levofloxacin and supplemental oxygen. He completed a five–day course of antibiotics and was discharged only on his home medication of minocycline. Two days after discharge, the patient returned with the same symptoms as his initial presentation. He reported that he had initially improved as an outpatient. However, his symptoms started to recur within 24 hours of discharge and worsened to require urgent reevaluation. Past medical history was significant for two episodes of pneumonia requiring hospitalization at ages 6 and 13, seasonal allergies on occasional antihistamine, and acne vulgaris on minocycline. Physical exam revealed a heart rate of 117 bpm, respiratory rate of 22 bpm, and oxygen saturation of 95% on room air. Temperature and blood pressure were normal. He appeared ill although non–toxic and was comfortably tachypneic. Lung exam was significant for decreased aeration and bibasilar crackles. The remainder of the physical exam was normal. A chest xray showed interval improvement of bilateral multilobar infiltrates. A chest CT scan demonstrated bilateral ground glass and consolidative opacities, most pronounced in the posterior aspect of the left lower lobe, with predominantly peripheral pulmonary opacifications. His white count was elevated to 17.5 × 109 cells/l with 64% neutrophils, 22% eosinophils, and 11% lymphocytes. Comprehensive metabolic panel, urinalysis, hemoglobin, hematocrit, and platelet count were normal. Immunoglobulins were normal except IgE which was 135 kU/L, greater than 2 standard deviations above the mean. Bronchoscopy with bronchoalveolar lavage was performed and demonstrated 91% eosinophils, confirming the diagnosis of minocycline–induced eosinophilic pneumonia. Discussion: First described in 1979, minocycline–induced eosinophilic pneumonia is a rare diagnosis, with only approximately 50 cases reported worldwide. The disorder is usually characterized by systemic symptoms, peripheral eosinophilia, and pulmonary infiltrates within days to weeks of beginning minocycline. On presentation, the condition is often confused with an infectious pneumonia. However, generally the only treatment required is discontinuation of minocycline. After reevaluation of our patient’s history it became clear that he improved because minocycline was withheld and not because he received antibiotics.
Minocycline is an important, albeit rare, cause of eosinophilic pneumonia. Recognition of minocycline as an inciting agent is critical to avoid exposing a patient to unnecessary treatment with antibiotics.