Diphtheria (dif-THEER-e-uh) is a serious bacterial infection usually affecting the mucous membranes of your nose and throat. Diphtheria typically causes a sore throat, fever, swollen glands and weakness. But the hallmark sign is a sheet of thick, gray material covering the back of your throat, which can block your airway, causing you to struggle for breath.

Diphtheria is extremely 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 damage your heart, kidneys and nervous system. Even with treatment, diphtheria can be deadly — up to 3 percent of people who get diphtheria die of it. The rate is higher for children under 15.

Symptoms Causes Risk factors Complications Prevention

Diphtheria signs and symptoms usually begin two to five days after a person becomes infected and may include:

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

In some people, infection with diphtheria-causing bacteria causes only a mild illness — or no obvious signs and symptoms at all. Infected people who remain unaware of their illness are known as carriers of diphtheria, because they can spread the infection without being sick themselves.

Skin (cutaneous) diphtheria

A second type of diphtheria can affect the skin, causing the typical pain, redness and swelling associated with other bacterial skin infections. Ulcers covered by a gray membrane also may develop in cutaneous diphtheria.

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.

When to see a doctor

Call your family doctor immediately if you or your child has been exposed to someone with diphtheria. If you're not sure whether your child has been vaccinated against diphtheria, schedule an appointment. Make sure your own immunizations are current.

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