Diphtheria is an acute infectious disease caused by the bacteria Corynebacterium diphtheriae.

Diphtheria spreads through respiratory droplets (such as those produced by a cough or sneeze) of an infected person or someone who carries the bacteria but has no symptoms. Diphtheria can also be spread by contaminated objects or foods (such as contaminated milk). Symptoms usually occur 2 to 5 days after you have come in contact with the bacteria.

The bacteria most commonly infects the nose and throat. The throat infection causes a gray-to-black, tough, fiber-like covering, which can block the airways. In some cases, diphtheria may first infect the skin, producing skin lesions.

Once infected, dangerous substances produced by the bacteria can spread through your bloodstream to other organs, such as the heart, and cause significant damage. The most common complication is inflammation of the heart muscle (myocarditis). The nervous system is also frequently and severely affected, and may result in temporary paralysis.

Diphtheria may be mild or severe. Some people may not have symptoms. In others, the disease can slowly get worse.

Because of widespread and routine childhood DPT immunizations, diphtheria it is now rare in many parts of the world. There are fewer than 5 cases of diphtheria a year in the United States.

Risk factors include crowded environments, poor hygiene, and lack of immunization.

• Sore throat (may range from mild to severe)
• Painful swallowing
• Hoarseness
• Drooling (suggests airway blockage is about to occur)
• Fever
• Chills
• Bloody, watery drainage from nose
• Croup-like (barking) cough
• Stridor, difficulty breathing, or rapid breathing
• No breathing
• Bluish coloration of the skin
• Skin lesions (usually seen in tropical areas)

The health care provider will perform a physical exam and look inside your mouth. This may reveal a gray-to-black covering (pseudomembrane) in the throat, enlarged lymph glands, and swelling of the neck or larynx.

Tests used may include:

• Gram stain or throat culture to identify Corynebacterium diphtheriae
• Electrocardiogram (ECG)

If the health care provider thinks you have diphtheria, treatment should be started immediately, even before test results are available.

Diphtheria anti-toxin is given as a shot into a muscle or through an IV (intravenous line). The infection is then treated with antibiotics, such as penicillin or erythromycin.

People with diphtheria may need to stay in the hospital while the anti-toxin is being received. Other treatment may include:

• Fluids by IV
• Oxygen
• Bed rest
• Heart monitoring
• Insertion of a breathing tube
• Correction of airway blockages

Anyone who has come into contact with the infected person should be immunization or booster shots against diphtheria. Protective immunity lasts only 10 years from the time of vaccination, so it is important for adults to get a booster of tetanus-diphtheria (Td) vaccine every 10 years.

Those without symptoms but who carry diphtheria should be treated with antibiotics.

The death rate is 10%. Recovery from the illness is slow.

The diphtheria toxin can damage the heart, nervous system, kidneys, or other organs. This may lead to:

• Myocarditis, which can lead to heart failure
• Nerve problems such as peripheral neuritis, which can cause uncoordinated movements and paralysis
• Kidney damage
• Inflammation of the kidneys (nephritis)

Contact your health care provider if you have come in contact with diphtheria.

Remember that diphtheria is a rare disease. Diphtheria is also a reportable disease, and any cases are often publicized in the newspaper or on television. This helps you to know if diphtheria is present in your area.

Routine childhood immunizations and adult boosters prevent the disease. See diphtheria immunization (vaccine).