What is a sore throat?

Causes and Symptoms

Sore throat, termed pharyngitis by medical practitioners,
is a common cause of patient discomfort and visits to the doctor’s office. Though
many people equate sore throat with strep throat, in reality there are many
infectious and noninfectious causes of this symptom. Sore throat can even be a
sign of disease in another part of the body. The sensation, which may be described
by sufferers as scratchy, raw, tight, burning, or achy, may last from minutes to
months, depending on the underlying cause, and may be accompanied by related
complaints such as fever, runny nose, hoarseness, or
difficulty swallowing.

Most sore throats are caused by infection in the upper respiratory tract,
including the ears, nose, and sinuses as well as the throat and tonsils. Research
has demonstrated that more than half of these infections are caused by common
viruses. Epstein-Barr virus, which causes mononucleosis, accounts for less than 10 percent. Most of the
remainder are caused by various bacteria. Of the bacterial causes,
strep, more specifically group A beta-hemolytic
Streptococcus
, is the most common pathogen.
Additional bacterial causes include species of
Staphylococcus
,
Hemophilus, Mycoplasma, non-group A streptococcus,
and others. More rarely, fungi may account for a larger portion
of throat infections in patients with weakened immune defenses.

Noninfectious causes of sore throat are quite varied. Although most are self-limited (resolving over time without treatment), some represent serious illness. These come into consideration especially if the duration of symptoms is longer than usual and if other aspects of the patient’s health history suggest the likelihood of secondary causes.

Traumatic causes of throat discomfort include swallowing foreign objects, such as
fish bones; thermal injury from a hot beverage; chemical injury from an ingestion,
such as bleach; and external force from a blow to the neck. Environmental
irritants, such as smoke and solvent fumes or allergies to dusts and pollens, cause symptoms in
susceptible, exposed persons. Regurgitated stomach acid, such as from
acid reflux
disease, causes discomfort, which may be more pronounced when
the patient is lying down. Enlargement of the thyroid gland or the salivary
glands, cysts arising from embryonic structures such as the thyroglossal duct, or
inflammation of lymph nodes can exert local pressure on the throat itself or on
adjacent nerves, thereby eliciting symptoms. Cancer is the most ominous cause of
sore throat symptoms, and it needs to be considered in patients with risk factors such as smoking
and excessive alcohol consumption.

Considering this expansive list of possibilities, which does not include every
possible cause of sore throat, it is evident that the expedient diagnosis of sore
throat is challenging. Though most sore throats resolve without treatment or
complication, the practitioner must consider the possibility of rarer but
potentially life-threatening diseases. The initial history and physical
examination are sufficient in most cases to separate those patients who are likely
to have an infectious cause from those who are unlikely to have one. Since most
patients are initially concerned about the possibility of strep throat and the
need for antibiotics, clinical algorithms, such as the Centor score, have been
developed to assist this process. By tallying associated signs, symptoms, and
patient characteristics, the practitioner may increase diagnostic accuracy. In
some cases, additional testing, such as a rapid streptococcal antigen throat swab
or a culture, is needed.

The search for noninfectious causes often begins when the patient returns with
persisting symptoms. Since most throat infections resolve within a week or two,
lingering discomfort suggests the need for further evaluation. In many cases,
additional historical information from the patient and a follow-up physical
examination will significantly narrow the list of possibilities. Clues such as
weight loss, hoarseness, and a history of cigarette smoking and alcohol
consumption increase the probability of throat cancer. Occupational information
may uncover exposure to noxious dust or vapors. In difficult cases, diagnosis may
require examination and biopsy of the throat during a procedure called laryngoscopy.

Treatment and Therapy

The treatments of noninfectious sore throat are as varied as the diagnoses
themselves. The treatment of infectious sore throat depends on the underlying
cause, ranging from rest, fluids, and analgesics (painkillers) for viruses to
antibiotics for certain bacteria and fungi. Penicillin has been the mainstay of
strep throat treatment since the mid-twentieth century. Before the discovery of
penicillin, throat infection sometimes resulted in serious complications, such as
rheumatic
fever (which damages the heart valves) and glomerulonephritis
(which damages the kidneys). Although group A Streptococcus
pyogenes has remained remarkably sensitive to penicillin, reports have
suggested that the treatment of strep throat is becoming more complex. The
presence of other bacteria in the throat, some of which have developed the ability
to inactivate penicillin, may actually protect the strep bacteria from the
antibiotic. Interestingly, some research suggests that antibiotic treatment very
early in the course of disease may even increase the likelihood of subsequent
recurrence. Infections by bacteria other than strep or by fungi are treated with
other antibiotic and antifungal drugs.

Given this scenario, one may wonder why doctors do not treat everyone with
antibiotics, rather than going to the trouble and expense of diagnosing strep
throat. Antibiotic treatment is complicated by many factors, including cost, drug
interactions, and the potential for allergic reactions. Widespread use has led to
the development of antibiotic-resistant strains of “super bacteria,” which are
very difficult if not impossible to treat.

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