INFECTIOUS DISEASE Bacterial • Lyme disease • Toxic shock syndrome • Tetanus • Strep throat • Tuberculosis • Whooping cough • Plague • Diphtheria • Typhoid fever • Cholera • Rocky Mountain spotted fever • Botulism • Ehrlichiosis • Tularemia • MRSA infection • Whipple's disease • Brucellosis

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Diphtheria (dif-THEER-e-uh) is a serious bacterial infection, usually affecting the mucous membranes of your nose and throat. The disease typically causes a bad sore throat, fever, swollen glands and weakness. But the hallmark sign is a thick, gray covering in the back of your throat that can make breathing difficult. Diphtheria can also infect your skin.

Years ago, diphtheria was a leading cause of death among children. Today, diphtheria is rare in the United States and other developed countries thanks to widespread vaccination against the disease.

Medications are available to treat diphtheria. However, in advanced stages, diphtheria can cause damage to your heart, kidneys and nervous system. Nearly one out of every 10 people who get diphtheria die of it.

Signs and symptoms of diphtheria may include:

• A sore throat and hoarseness
• Painful swallowing
• Swollen glands (enlarged lymph nodes) in your neck
• A thick, gray membrane covering your throat and tonsils
• Difficulty breathing or rapid breathing
• Nasal discharge
• Fever and chills
• Malaise

Signs and symptoms usually begin two to five days after a person becomes infected, but they may take as many as 10 days to appear. You may mistake diphtheria in its initial stages for a bad viral sore throat. Other early symptoms include a mild fever and swollen glands in the neck — signs and symptoms of other, much more common types of infection such as strep throat or mononucleosis.

The bacterium that causes diphtheria attacks mucous membranes that line the nose and throat and cover the tonsils. The throat becomes inflamed. The inflammation may spread to the voice box (larynx) and may make your throat swell, narrowing your airway.

A hallmark sign
The bacteria may produce a toxin that can lead to a thick, gray covering in your nose, throat or airway — a marker of diphtheria that separates it from other respiratory illnesses. This covering is usually fuzzy gray or black and causes breathing difficulties and painful swallowing.

In more advanced stages, a person with diphtheria may have severe difficulty breathing and may show signs of respiratory distress such as rapid breathing, a rapid heartbeat and cold, clammy skin.

Some people become infected with diphtheria-causing bacteria, but they develop only a mild case of the illness and show no signs or symptoms of the disease. They're said to be carriers of the disease, because they may be contagious without showing signs or symptoms of illness.

Skin (cutaneous) diphtheria
Diphtheria occurs in two types. One type involves the mucous membranes of your nose and throat, and the other involves the skin. A wound infected with bacteria is typically red, painful and swollen. A wound infected with diphtheria-causing bacteria also may have patches of a sticky, gray material.

Although it's more common in tropical climates, cutaneous diphtheria also occurs in the United States, particularly among people with poor hygiene who live in crowded conditions.

In rare instances, diphtheria affects the eye.

The bacterium Corynebacterium diphtheriae causes diphtheria. Usually the bacteria multiply on or near the surface of the mucous membranes of the throat, where they cause inflammation. Some types of C. diphtheriae release a toxin, a poison, which can damage the heart, the brain and the nerves.

You contract diphtheria by inhaling airborne droplets exhaled by a person with the disease or by a carrier who has no symptoms. Diphtheria passes from an infected person to others through:

• Sneezing and coughing, especially in crowded living conditions (easily)
• Contaminated personal items, such as tissues or drinking glasses that have been used by an infected person (occasionally)
• Contaminated household items, such as towels or toys (rarely)

You can also come in contact with diphtheria-causing bacteria by touching an infected wound.

People who have been infected by the diphtheria bacteria and who haven't been treated can infect nonimmunized people for up to six weeks — even if they don't show any symptoms.

Children younger than 5 years old and adults older than 60 are particularly at risk of contracting diphtheria, as are:

• People living in crowded or unsanitary conditions
• Undernourished people
• Children and adults who don't have up-to-date immunizations
• People who have a compromised immune system

Diphtheria is rare in the United States and Europe, where health officials have been immunizing children against it for decades. In the United States, fewer than five cases have occurred each year since 1980, according to the Centers for Disease Control and Prevention.

However, diphtheria is still common in developing countries where immunization rates are low. For example, large outbreaks of diphtheria occurred in the 1990s throughout Russia and the independent countries of the former Soviet Union, resulting in some 5,000 deaths. Control measures have since been implemented, but a risk of diphtheria remains in those areas.

Most cases of diphtheria occur in unvaccinated or inadequately vaccinated people. Diphtheria poses a threat to U.S. citizens who may not be fully immunized and who travel to other countries or have contact with immigrants or international travelers coming to the United States.

Call your family doctor immediately if you or your child has signs or symptoms of diphtheria or if anyone in your family is exposed to diphtheria. If you're not sure if your child has been vaccinated against diphtheria, make an appointment. Make sure your own immunizations are current.

Doctors may suspect diphtheria in a sick child who has a sore throat with a gray membrane covering the tonsils and throat. Doctors confirm the diagnosis by taking a sample of the membrane from the child's throat with a swab and having the bacteria grown (cultured) in a laboratory.

Doctors can also take a sample of tissue from an infected wound and have it tested in a laboratory, to test for the type of diphtheria that affects the skin (cutaneous diphtheria).

If a doctor suspects diphtheria, treatment begins immediately, even before the results of bacterial tests are available.

Left untreated, diphtheria can lead to:

• Breathing problems. Diphtheria-causing bacteria may produce a toxin, a poison. This toxin damages tissue in the immediate area of infection — the nose and throat, for example. This localized infection produces a tough, gray-colored membrane — which is composed of dead cells, bacteria and other substances — on mucous membranes inside your nose and throat. This membrane, or covering, is dangerous because it can obstruct breathing.
• Heart damage. The diphtheria toxin may spread through your bloodstream and damage other tissues in your body, such as your heart muscle. One complication of diphtheria is inflammation of the heart muscle (myocarditis). Signs and symptoms of myocarditis include fever, vague chest pain, joint pain and an abnormally fast heart rate. Damage to the heart from myocarditis may be only slight, showing up as minor abnormalities on an electrocardiogram, or very severe, leading to congestive heart failure and sudden death.
• Kidney damage. The diphtheria toxin may damage the kidneys, affecting their ability to filter wastes from the blood.
• Nerve damage. The toxin can also cause nerve damage, targeting certain nerves such as those to the throat, making swallowing difficult. Nerves to the arms and legs may also become inflamed, causing muscle weakness. In severe cases, nerves that help control the muscles used in breathing may be damaged, leading to paralysis of these muscles and trouble breathing.

With treatment, most people with diphtheria survive these complications, but recovery is often slow. Diphtheria is fatal in approximately one in 10 cases.

Diphtheria is a serious illness. Doctors treat it immediately and aggressively with these medications:

• An antitoxin. After doctors confirm that a person has diphtheria, the infected child or adult receives a special antitoxin. The antitoxin neutralizes the diphtheria toxin already circulating in your body. The antitoxin is injected into a vein (intravenously) or into a muscle (intramuscular injection). But first, doctors may perform skin allergy tests to make sure that the infected person doesn't have an allergy to the antitoxin. Persons who are allergic must first be desensitized to the antitoxin. Doctors accomplish this by initially giving small doses of the antitoxin and then gradually increasing the dosage.
• Antibiotics. Diphtheria is also treated with antibiotics, such as penicillin or erythromycin. Antibiotics help kill bacteria in the body, clearing up infections. Antibiotics reduce to just a few days the length of time that a person with diphtheria is contagious.

Children and adults who have diphtheria often need to be in the hospital for treatment. They may be isolated in an intensive care unit because diphtheria can spread easily to anyone not immunized against the disease.

Doctors may remove some of the thick, gray covering in the throat if the covering is obstructing breathing.

There may be other complications of diphtheria that need treatment. Inflammation of the heart (myocarditis) is treated with medications. In advanced cases, a person with diphtheria may need the assistance of a machine that helps them breathe (ventilator) until the infection is successfully treated.

Preventive treatments
If you've been exposed to a person infected with diphtheria, see a doctor for testing and possible treatment. Your doctor may give you a prescription for antibiotics to help prevent you from getting the infection. You may also need a booster dose of the diphtheria vaccine.

Doctors treat people who are found to be carriers of diphtheria with antibiotics to clear their systems of the bacteria, as well.

Before antibiotics were available, diphtheria was a common illness in young children. Today, the disease is not only treatable but also preventable with a vaccine.

The diphtheria vaccine is usually combined with vaccines for tetanus and whooping cough (pertussis). Tetanus is a bacterial infection that leads to stiffness of the jaw and other muscles. Whooping cough is a bacterial infection of the respiratory tract. The three-in-one vaccine is known as the diphtheria, tetanus and pertussis, or DTP, vaccine. The latest version of this immunization is known as the DTaP vaccine.

The diphtheria, tetanus and pertussis vaccine is one of the childhood immunizations that doctors in the United States recommend begin during infancy. The vaccine consists of a series of five shots, typically administered in the arm or thigh, and is given to children at ages:

• 2 months
• 4 months
• 6 months
• 15 to 18 months
• 4 to 6 years

The diphtheria vaccine is very effective at preventing diphtheria. But there may be some side effects. Some children may experience a mild fever, fussiness, drowsiness or tenderness at the site of the injection after a diphtheria, tetanus and pertussis shot. Ask your doctor what you can do for your child to minimize or relieve these effects.

Rarely, the diphtheria, tetanus and pertussis vaccine causes serious complications in a child, such as an allergic reaction (hives or a rash develops within minutes of the injection), seizures or shock — complications which are treatable.

Some children — such as those with progressive brain disorders — may not be candidates for the diphtheria, tetanus and pertussis vaccine. But, the number of children to whom these restrictions apply is small.

You can't get diphtheria from the vaccine.

Booster shots
After the initial series of immunizations in childhood, booster shots of the diphtheria vaccine are needed to help you maintain immunity. That's because immunity to diphtheria fades with time.

The first booster shot is needed around age 12, and then every 10 years after that — especially if you travel to an area where diphtheria is common. Ask your doctor whether you're up-to-date on your immunizations. Be sure your child is as up-to-date as possible on childhood vaccinations before starting child care or school.

A booster shot of the diphtheria vaccine is given in combination with a booster shot of the tetanus vaccine. The tetanus-diphtheria (Td) vaccine is given by injection, usually into the arm or thigh.

Doctors recommend that anyone older than age of 7 who has never been vaccinated against diphtheria receive three doses of the Td vaccine.

Recovering from diphtheria requires lots of bed rest. You may need to stay in bed for up to six weeks or until you make a full recovery. Rest is particularly important if your heart has been affected. Strict isolation while you're contagious also is important to prevent spread of the infection. Careful hand washing by everyone in your house is a good way to help avoid spread of the infection. Because of pain and difficulty swallowing, you may need to get your nutrition through liquids and soft foods for a while.

Once you recover from diphtheria, you'll need a full course of diphtheria vaccine to prevent a recurrence. Having diphtheria doesn't guarantee you lifetime immunity. You can get diphtheria more than once if you're not fully immunized against it.