What Causes the “Common Cold”?

Upper respiratory tract infection (URI) is the most common acute minor illness diagnosed in a pediatrician’s office. Generally, the child has rhinorrhea and mild irritability and may also have earache or sore throat. The physician must decide if the child’s symptoms and signs are caused by a viral infection or are indicative of a bacterial infection such as otitis media, sinusitis, or even pneumonia. More than 200 viruses cause colds, although rhinoviruses comprise more than one-third of this number. Viral infection confers serotype-specific, lifelong immunity, but more than 100 serotypes of rhinovirus exist, so the chance of sequential infections with different serotypes is great. Parainfluenza, metapneumovirus, and respiratory syncytial viruses also cause URI.

How Does a “Cold” Present?

Children initially present with mucoid (“clear”) rhinorrhea, pharyngeal irritation, and some systemic complaints such as malaise. Fever occurs variably. Infants and younger children may present only with nasal discharge and irritability. After 2 or 3 days, the nasal discharge thickens and becomes cloudy and discolored from the shedding of epithelial cells and white blood cells; the color change does not necessarily indicate a bacterial infection. In patients with a cold, the physical examination is generally unremarkable except for reactive cervical lymphadenopathy and nasal discharge. Bacterial complications such as otitis media, sinusitis, or pneumonia are suggested by specific findings related to the system involved. Otitis media is diagnosed when the tympanic membrane is bright red or yellow, bulges, and has loss of landmarks and mobility (see Chapter 30). Sinusitis and pneumonia are discussed in Chapter 64. The signs and symptoms of the usual cold last 5 to 14 days. Parents are often concerned that their child has had a persistent cold for weeks or even months. The most likely explanation for the parent’s observation is that the child has experienced sequential viral infections rather than one persistent infection. On average, a child may experience 6 to 8 colds in a year. This number may be higher with daycare attendance.

What Treatment, If Any, Is Recommended for a Cold?

No medications have been shown to effectively decrease viral shedding or the duration of symptoms. In most situations, the most appropriate therapy is to maintain good fluid intake and manage symptoms such as fever and myalgia with acetaminophen or ibuprofen. Nonpharmacologic interventions such as mist, application of normal saline nose drops, bulb suctioning of the nostrils, and elevation of the head of the bed may be beneficial in some patients. Pharmacologic interventions, such as antihistamines, decongestants, expectorants, and cough suppressants, generally trade one set of symptoms for another. The most common complications of pharmacotherapy are irritability and sedation. In older children and adults, decongestants (sympathomimetics) may be helpful. Antibiotics are not useful in viral infections.

KEY POINTS