A 74-year-old man, in excellent physical condition and doing regular intense cycling, was evaluated for transient episodes of thoracic discomfort over a period of several months. His medical history only included a right inguinal hernia, surgically treated, and an abdominal aortic aneurysm measured at 46 mm and treated medically. Physical examination did not reveal much information. The patient did not report gastroesophageal reflux, dysphagia, or history of digestive occlusion. The patient had normal weight and had no trauma history. He had no nicotine or alcohol-dependent behaviors. Vital signs were within normal values. Laboratory test results were normal. Functional status was normal, without anomalies of pulmonary function tests or arterial blood gases. The ECG did not reveal any anomaly.

A 64-year-old man with a past medical history of alcoholic cirrhosis with resultant hepatorenal syndrome requiring kidney and liver transplantation 10 years previously sought treatment at the ED with progressive lower-extremity edema and dyspnea. After noting worsening shortness of breath and cough as an outpatient, he had been referred to a pulmonary clinic and was undergoing a workup for interstitial lung disease (ILD). He had been started on prednisone 40 mg/d after a lung biopsy 4 months before admission. He was also receiving chronic immunosuppression with tacrolimus and mycophenolate mofetil. He had noted worsening of edema since starting prednisone.

A 24-year-old man, never smoker, with no medical or surgical history, not currently on medications, presented to the ED with a second episode of gross hemoptysis, 4 months after an initial episode that had not previously been evaluated. He described the current episode of hemoptysis as "enough to fill the sink"; however, he did not further quantify. He has no history of recurrent epistaxis, hematemesis, or other evidence of clotting disorder. He denied any fevers, chills, night sweats, or recent travel. He denied any sick contacts and has no history of TB exposure or risk factors. The patient denied any shortness of breath, wheezing, or chest pain. He had no lower extremity pain or swelling. He routinely exercises and generally lives a healthy lifestyle. He is a health care worker who has not routinely worked with patients infected with SARS-CoV-2, although he received his second (of two) COVID-19 vaccines 4 days before presentation.

A 58-year-old woman was referred to our department with a cough of 1 year duration; her condition was unresponsive to the administration of inhaled steroid and beta-2 agonists. She denied the presence of dyspnea, chest pain, or other extrapulmonary symptoms. She was a never-smoker with a negative medical history and no occupational or domestic exposures. There was no history of cancer, gastroesophageal reflux disease, asthma, allergic rhinitis, or other allergies.

A 24-year-old previously healthy woman was brought to the hospital for acute altered mental status. One week prior to presentation, she had developed a sore throat, nausea, and vomiting. At that time, SARS-CoV-2 polymerase chain reaction and rapid streptococcal pharyngitis test results were both negative. On the day prior to presentation, the patient had developed an erythematous painful rash on her left arm. The following day she was noted to be agitated, combative, and having trouble communicating, prompting ED evaluation. In the ED, the patient was tachycardic to 108 beats/min and tachypneic to 30 breaths/min but normotensive and afebrile. Her initial workup was notable for leukocytosis with bandemia, acute liver injury with coagulopathy, and acute renal failure. She was intubated, transferred to our hospital, and admitted to the MICU. The patient's medical history was notable for obesity and oral contraceptive use. She had no family history of autoimmune, rheumatologic, or hematologic disorders. She was a student and worked part time in retail. She had no recent travel or outdoor exposure. The patient's family was unaware of any tobacco or drug use but did report that she drank socially.

A 49-year-old woman presented to the ED with sudden onset abdominal pain, nausea, and vomiting. Her medical history included an uncomplicated gastric lap band surgery 9 years ago and subsequent removal of lap band after 6 years. She had a Roux-en-Y gastric bypass and cholecystectomy 5 months prior to the current presentation. The patient had been diagnosed with asthma and was prescribed an inhaled corticosteroid that she used only as needed. The patient denied smoking and heavy alcohol consumption. She was currently employed as a scrub technician in a local surgical center.

A 60-year-old man with a history of COPD, uncontrolled diabetes (hemoglobin A1c, 10.6%), obesity (BMI, 33.4), and a family history of Ehlers-Danlos syndrome came to the ED with several hours of acute-onset severe left mid-axillary pleuritic chest pain without alleviating factors. The pain had no specific triggers, including activities or heavy meals. It was associated with nausea, chills, and diaphoresis; also, it was preceded by a few weeks of subacute flulike symptoms for which he did not seek medical attention. He denied previous similar symptoms, recent trauma, or surgeries.

A 70-year-old woman was transferred to our ED from an outside ED for hypoxemia. Three weeks earlier, an inpatient evaluation for syncope revealed a right intraventricular filling defect, multiple pulmonary nodules, pulmonary emboli, and a left breast mass. She underwent breast biopsy, was started on rivaroxaban, and was discharged with outpatient follow-up. She experienced progressively worsening dyspnea, prompting a return to the outside ED, where she was found to be severely hypoxemic and was intubated. Her medical history included diabetes, hypertension, hyperlipidemia, COPD, hypothyroidism, diastolic heart failure, and a 40+ pack-year smoking history.

Hypersensitivity pneumonitis (HP) is an inflammatory and/or fibrotic disease affecting the lung parenchyma and small airways. It typically results from an immune-mediated reaction provoked by an overt or occult inhaled antigen in susceptible individuals. The chronic or fibrotic form of HP has a poor prognosis, especially when no inciting antigen is identified, which occurs in up to 60% of cases. We report two cases of HP associated with exposure to mold in foam pillows and a mattress, which has not previously been reported as a risk factor for HP. Given the high prevalence of foam in pillows and mattresses, mold in foam in bedding may explain many HP cases with a previously unrecognized cause. Early identification and avoidance of foam in bedding may prevent HP progression to end-stage pulmonary fibrosis and death.