What is Common Cold

The common cold, or acute coryza rhino-viral infection of the nasal passages and pharynx. Although the common cold causes generalised symptoms (malaise, tiredness), the rhinoviral infection itself is restricted to these areas.

Who gets Common Cold?

On average, individuals suffer two to three colds per year; young children may suffer more colds, and the elderly may suffer less colds.

Predisposing Factors

Young age, and close contact with individuals suffering from a cold, increases the likelihood of infection. Nasal mucus (for example on hands) or droplets are highly infectious, and spread is facilitated by overcrowding and poor ventilation.

Progression

60% of common colds are caused by rhinoviruses. The rest occur due to infection by coronavirus, influenza viruses, parainfluenza virus, respiratory syncytial virus, adenovirus, and enterovirus. In addition, the bacteria Mycoplasma pneumoniae and Chlamydia pneumoniae may cause common cold symptoms.

After cold infection, the viruses have an ‘incubation period’, during which they don’t cause cold symptoms, lasting from 12 hours to up to 5 days. Then a watery nasal discharge occurs, which becomes thick and yellowish in about 24 hours, and may last for up to a week. Uncommonly, secondary cold infection by bacteria may occur.

Other complications of the common cold include: nasal stuffiness, which may impair suckling in infants, spread of infection to sinuses (sinusitis) and middle ear (otitis media), and inflammation of the larynx (voice box), trachea or bronchi, causing a hoarse voice or a cough.

Probable Outcomes

The cold itself is a relatively mild, self-limiting disease. However, spread of the causative microbes to the lower respiratory tract may cause serious, even life-threatening disease in at-risk patients (very young or elderly, immunosuppressed). Secondary bacterial infection with subsequent spread may also cause serious disease in these populations.

How is Common Cold Diagnosed?

Investigations are generally not required for common cold symptoms lasting around 7 days or less. However, the cold symptom of a sore throat can pose difficulties in diagnosis of a cold, as it is not always clear whether the cause is bacterial or viral, nor whether the virus involved is a common cold virus or another such as Epstein Barr virus (glandular fever).

If the diagnosis of a cold is unclear, and it is important to make a definitive diagnosis, the following investigations may be done:

* Throat swab (to look for bacterial infection. Its use is controversial)
* Haemoglobin, blood film and white cell count
* Test for Epstein Barr virus (Paul Bunnel or monospot test)
* Random blood sugar (if diabetes causing repeated infection is suspected)

How is Common Cold treated?

The following common cold treatment is useful and commonly prescribed by Australian GPs:

* Adequate sleep and rest
* Paracetamol or aspirin
* Steam inhalations for a blocked nose
* Cough mixture for a dry cough
* Gargling aspirin in water or lemon juice for a sore throat

Unfortunately, most ‘cold’ medications available at the chemist (antihistamines, pseudoephidrine) have not been shown to be of proven benefit. Antibiotics do not limit the duration of common cold symptoms, nor do they decrease the likelihood of secondary bacterial infection.

Common Cold References

1. Cotran RS, Kumar V, Collins T. Robbins Pathological Basis of Disease Sixth Ed. WB Saunders Company 1999. pp347-48
2. Kumar P, Clark M. Clinical Medicine. Fourth Ed. WB Saunders, 1998. p769
3. Murtagh, J. General Practice. Second Ed. McGraw-Hill, 1998. pp 377-78 [4] Robinson MJ, Roberton DM. Practical Paediatrics. Fourth Ed. Churchill Livingstone, 1998. p422.

Drugs/Products Used in the Treatment of This Disease:

* Actacode
(Codeine phosphate)

* Actifed
(Pseudoephedrine hydrochloride; Triprolidine hydrochloride)

* Actifed CC Dry Cough
(Pholcodine)

* Action Cold and Flu Effervescent

* Actuss

* Avil Decongestant
(Ammonium chloride; Menthol; Pheniramine maleate)

* Benadryl Family Chesty Cough & Nasal Congestion
(Guaifenesin; Pseudoephedrine hydrochloride)

* Benadryl Family Dry Forte
(Dextromethorphan hydrobromide)

* Nurofen
(Ibuprofen)

* Sudafed Daytime/Nightime Relief Tablets
(Paracetamol, Pseudoephedrine hydrochloride, Triprolidine hydrochloride)

* Tamiflu
(Oseltamivir phosphate)

* Voltaren Rapid 12.5/ 25/ 50
(Diclofenac potassium)