Viral Upper Respiratory Tract Infection (URTI): This is the most common cause of nighttime cough, fever, and cold symptoms, often due to viruses such as rhinovirus, coronavirus, or influenza. The symptoms are typically self-limiting and include runny nose, sneezing, cough, and sometimes fever.

Acute Bronchitis: Often follows a viral upper respiratory infection, acute bronchitis can cause a persistent cough, which worsens at night, along with fever and other cold symptoms.
Sinusitis: An infection or inflammation of the sinuses can cause cough, especially at night, along with facial pain, headache, and fever.
Allergic Rhinitis: Allergies can lead to chronic or seasonal symptoms of runny nose, sneezing, and cough, which may worsen at night, though fever is less common.
Asthma: Especially in children, asthma can present with cough, wheezing, and shortness of breath, which can be exacerbated at night and may be accompanied by fever if there's an underlying infection.

Pneumonia: A bacterial or viral infection of the lungs that can present with cough, fever, and difficulty breathing. It's crucial to diagnose and treat promptly to prevent complications.
Pertussis (Whooping Cough): A highly contagious bacterial infection that causes severe coughing fits, which can be particularly dangerous in infants and young children.
Tuberculosis (TB): A bacterial infection that primarily affects the lungs and can cause chronic cough, fever, night sweats, and weight loss. Although less common, it's critical to consider, especially in high-risk populations.
Foreign Body Aspiration: Especially in young children, the aspiration of a foreign body can cause sudden onset of cough and respiratory distress, which is a medical emergency.

Cystic Fibrosis: A genetic disorder that leads to severe respiratory and digestive problems, including chronic cough, recurrent lung infections, and failure to thrive in children.
Immunodeficiency: Conditions that impair the immune system, such as HIV/AIDS or primary immunodeficiencies, can lead to recurrent or severe infections, including those causing cough and fever.
Interstitial Lung Disease: A group of disorders that affect the interstitial spaces of the lungs, including conditions like pulmonary fibrosis, which can cause chronic cough and shortness of breath.