4 Ways to Know Whether a Bacterial Infection Is Contagious

1. Identify the Infection

You can tell whether a cut on your arm is infected. The wound will be sore and red, and it may contain pus. The most common bacterial skin infection is staph, which lives on the skin of all humans and occasionally infects sores on your body if they are not cleaned regularly. Often, staph will turn a wound gray or build up a thick, smelly pus below the skin's surface. However, you won't be able to see the same signs if you have a bacterial infection in your internal organs.

2. Use Your Personal Experience

You may determine the type of infection you have and whether it's contagious if you have prior experience with the disease. For instance, if you have had strep throat before, you know that a severe sore throat and white patches around your tonsils probably mean you've caught the contagious infection again.

3. Get Tested

Some bacterial infections, such as methicillin-resistant Staphylococcus aureus (MRSA), are highly infectious but look no different than any other staph infection. If you suspect your cut or cough is contagious, your doctor must test to make sure you can return to work or school without spreading the disease to others. For example, if your doctor thinks you might have strep throat, he will rub a swab on the back of your throat and submit the culture to a lab. Infections of the skin and internal infections are usually diagnosed with blood cultures. Your doctor probably will prescribe antibiotics before the test results come back to reduce the time you remain contagious.

4. Common Contagious Bacterial Infections

In some cases, you may be able to determine whether you have a contagious bacterial infection even before your doctor recommends staying inside and away from others. Some common contagious infections include MRSA, syphilis and some types of tuberculosis.