Croup, medically known as laryngotracheobronchitis, is a common respiratory illness that primarily affects the upper airways of young children. It is typically caused by a viral infection, most frequently Parainfluenza viruses (PIV), though RSV and influenza can also be responsible. The virus is highly contagious and spreads easily among people of all ages. While adults can contract the viruses that cause croup, the resulting illness usually manifests differently than the classic symptoms seen in a child.
Understanding How Croup Spreads
The viruses responsible for croup transmit efficiently through respiratory droplets released into the air when an infected individual coughs, sneezes, or speaks. Direct contact with an infected person’s respiratory secretions is also a common route of transmission.
The virus can also survive on surfaces, known as fomites, allowing for indirect transmission. If an adult touches a contaminated object and then touches their mouth, nose, or eyes, they can introduce the pathogen into their system. The incubation period is typically between two and seven days before symptoms develop.
Infected individuals are contagious for a significant period, often starting before symptoms appear. Contagiousness usually lasts for about three to five days after symptom onset, or until the person has been fever-free without medication.
Croup Symptoms in Adult Cases
The viruses that cause croup are contagious to adults, but they rarely develop the severe, characteristic disease. This difference is mainly due to anatomy; adults possess wider, more developed airways than young children. When inflammation occurs in an adult’s larynx and trachea, the larger diameter prevents these passages from closing off easily.
Therefore, adults seldom experience the hallmark pediatric symptoms: the harsh, seal-like barking cough or the noisy breathing sound called stridor. When an adult contracts the virus, the illness commonly presents as a mild upper respiratory infection, similar to a common cold. Symptoms often include a runny nose, nasal congestion, a sore throat, and a low-grade fever.
A common specific symptom for adults is hoarseness or a loss of voice, known as laryngitis. This occurs because the viral inflammation focuses on the vocal cords, but the swelling does not significantly impede airflow. While the virus is transmissible, severe croup is rare in adults, though cases requiring medical intervention for breathing difficulties have been reported.
Practical Steps for Prevention
Adults caring for a symptomatic child can take steps to reduce their risk of contracting the virus. Frequent and thorough handwashing with soap and water remains one of the most effective methods for disrupting viral transmission. It is important to scrub hands after contact with the infected child, their toys, or respiratory secretions.
Avoid touching your face, especially your eyes, nose, and mouth, as this is how the virus enters the body after touching a contaminated surface. Regularly disinfecting frequently touched objects (fomites), such as doorknobs, remote controls, and countertops, can limit the spread of the pathogen. Wearing a well-fitting mask when providing close care, especially during coughing or sneezing, can reduce the inhalation of respiratory droplets.