Pimples develop when pores on the skin become clogged with too much oil (sebum), dead skin cells, or bacteria. Acne tends to occur most often during puberty when the sebaceous glands typically produce more sebum but can develop at any time.
A pimple is more likely to become infected when it is popped. Infected pimples also occur when a person has cystic acne.
Read on to find out more about causes, symptoms, and treatments.
Popping a pimple may cause it to become infected.
A bacterium known as Propionibacterium acnes lives naturally on the skin. It is typically harmless, but when a sebaceous gland becomes blocked, it can start to reproduce and trigger an immune response, causing the pimple to become inflamed and grow larger.
Popping pimples can cause an infection because bacteria can enter the wound, or it can rupture the pustule inside the skin.
Cystic acne is the most severe form of acne, where pimples become large and pus-filled. This form of acne is more likely to cause scarring.
Skin infections such as boils and impetigo are caused by a staph bacteria called Staphylococcus aureus (S. aureus) and may be more challenging to treat.
Symptoms and diagnosis
Unlike a standard pimple, infected pimples can run deep into the skin and create a bigger, more painful bump.
Infected pimples may have the following symptoms:
- more obvious than regular pimples
- larger and redder in color due to inflammation
- take longer to heal than a regular pimple
- may be painful or sensitive to touch
- may be filled with pus
A pimple infected with S. aureus may be a boil. Boils are contagious, and although the infections are usually minor, a person might experience the following symptoms:
- red, painful lumps, typically on the neck, face, or buttocks
- a high temperature
- generally feeling unwell
Staph infections may also cause impetigo, which is a highly contagious skin infection. Small, itchy or painful blisters or sores usually appear on the hands or face first but can spread to other parts of the body. With treatment, impetigo usually clears up within 10 days. It is common in children.
Rosacea can also cause infected pimples. Rosacea is a long-term condition that usually causes pimples and redness on the face, sometimes with a burning or stinging sensation.
Anyone who is unsure what the infected bump on their skin is should see a doctor or a dermatologist, (skin doctor) for diagnosis.
Image credit: James Heilman, MD, 2010
Cutaneous abscess caused by Staphylococcus aureus
Image credit: Gregory Moran, M.D
Image credit: RicHard-59, 2014
Treating an infected pimple involves killing the bacteria that causes the infection. Medications to treat regular pimples will not treat infected pimples, although they can help reduce the spread to other areas.
When an infection is severe, a doctor may prescribe antibiotics, which can help reduce bacteria and inflammation. However, they may be less effective if a person takes them lots of times. Antibiotics are available as creams or oral tablets.
To treat an infected pimple at home, a person can use the following:
- A warm compress. Gently apply a warm compress to the infected pimple twice a day. This can bring the pus, sebum, or debris closer to the surface of the skin. Avoid pressing down on the pimple, as this can push its contents deeper into the skin.
- Apply benzoyl peroxide. This is an over-the-counter (OTC) cream that kills bacteria. Products containing this chemical are available online.
- Keep the area clean. Avoid touching the pimple, and clean it regularly to stop the infection from spreading and creating more infected pimples. This is especially important for people who have a staph infection.
Other tips that can help to treat and prevent infected pimples include:
- avoiding tight clothing, such as gym clothes, near the pimple
- changing bed sheets and clothes regularly
- avoiding scratching or popping pimples as this can increase the risk of further infection
- avoiding using makeup around the affected area
If the infection does not go away after a couple of weeks, or the symptoms are very severe, more invasive treatments may be necessary. Options could include laser surgery or light therapy to kill the bacteria causing the infection.
When to see a doctor
A person should consult their doctor or dermatologist if an infected pimple does not heal after several weeks.
Infected pimples can often be treated using OTC medication and home remedies, but severe infections may require antibiotics. The infection may take several weeks to disappear.
Anyone who is experiencing inflammation, infection, or pimples near the eyes should see a doctor. A person should also see a doctor if their symptoms do not improve after a couple of weeks or get worse.
If a person has a pimple that is unusually large and painful, it could be a boil or skin abscess caused by an infection. If a person suspects this is the cause, they should consult their doctor to find the most appropriate treatment.
Most people will have pimples at some time or another, but it is essential not to pop them or expose them to bacteria, or they may get infected. An infected pimple will usually clear up after a few weeks without the need for medical treatment.
In severe cases, however, more invasive treatments may be necessary to kill the bacteria causing the infection. It is important to consult a doctor if a more serious condition is suspected, as infected pimples can cause permanent scarring or may be contagious.