A skin infection is inflammation of the skin caused by bacteria, fungi, viruses, or parasites. It can lead to redness, itching, spots or lesions, pain, or pus on the skin.
There are many types of skin infections, including boils, erysipelas, fungal infections, candidiasis, herpes, and scabies. They are more common in people with weakened immune systems, but can also occur in otherwise healthy people.
Treatment for a skin infection depends on the specific type and what is causing it. A dermatologist typically recommends medications that target the microorganism responsible for the infection.
Main types
The main types of skin infections are:
1. Boils
A boil (furuncle) is a skin infection mainly caused by the bacterium Staphylococcus aureus, which can be found naturally on the skin and mucous membranes.
This type of skin infection can cause a tender, pus-filled lump that may enlarge over time. Symptoms can include pain, warmth in the area, redness, and sensitivity to touch.
What to do: Apply a warm compress about 3 times a day, and wash the area with warm water and mild soap. Never squeeze a boil, because this can worsen inflammation and infection and make it harder to treat.
In some cases, a dermatologist may recommend draining the boil to remove pus, along with antibiotics to treat the infection.
2. Erysipelas
Erysipelas is an infection of the superficial layer of the skin caused by the bacterium Streptococcus pyogenes (strep A). It can enter through breaks in the skin, such as a wound or an insect bite.
It can also develop due to a chronic venous ulcer or from poor nail care, or in association with athlete’s foot.
Erysipelas usually affects the legs or feet, and risk is higher in people with obesity, poorly controlled diabetes, eczema, or leg ulcers.
What to do: Treatment usually includes antibiotics prescribed by a dermatologist, pain relievers to reduce discomfort, and rest with the affected leg elevated.
3. Cellulitis
Cellulitis is a skin infection caused by Staphylococcus or Streptococcus bacteria that affect deeper layers of the skin.
These bacteria can enter through injuries such as a wound, cut, or insect bite, or through skin conditions like eczema, dermatitis, or fungal infections.
Cellulitis commonly causes swelling, pain, warmth, and redness in the area, and it may also be associated with fever, chills, and weakness.
What to do: Bacterial cellulitis is treated under the guidance of a primary care provider or infectious disease specialist, usually with antibiotics taken by mouth or given through an IV.
4. Impetigo
Impetigo is a contagious skin infection caused by bacteria that lead to small sores containing pus that form crusts.
It is common in childhood and can spread easily from one child to another, so it should always be evaluated by a pediatrician.
What to do: See a pediatrician or dermatologist, who may recommend antibiotic ointments. Important care measures include not picking off scabs, keeping the area clean, bathing daily, and applying the medication right after bathing.
5. Athlete’s foot
Athlete’s foot is a fungal skin infection caused by fungi in the Trichophyton genus. It can cause itching, redness, scaling, and odor, especially between the toes.
These fungi can live on the skin without causing symptoms, but moisture or excessive heat between the toes can allow them to multiply and trigger infection.
What to do: Treatment should be guided by a dermatologist, who may recommend antifungal creams or, in more severe cases, oral antifungal medications.
6. Candidiasis
Candidiasis is a skin infection caused by Candida fungus, and it can cause itching and red, moist lesions.
It most often affects skin folds such as under the breasts, the groin, the armpits, the nails, or between the fingers, although it can occur anywhere on the body.
It can also affect mucous membranes, such as the mouth, intestines, or the vagina, anal, or penile area.
What to do: Treatment is usually done by a dermatologist using antifungal medication in cream or ointment form or oral tablets.
7. Balanitis
Balanitis is an infection of the head of the penis, most often related to Candida albicans infection. It can also happen due to a bacterial infection or, in some cases, an allergic reaction.
Common symptoms include redness, itching, and swelling of the head of the penis, and it may also cause swollen lymph nodes in the groin.
What to do: See a urologist to identify the cause. Proper hygiene and wearing breathable cotton underwear may be recommended. In some cases, corticosteroid, antibiotic, or antifungal creams or ointments may be used.
8. Scabies
Scabies is a skin infection caused by the mite Sarcoptes scabiei, leading to intense itching that often worsens at night and redness of the skin.
It can spread easily through skin-to-skin contact or by sharing contaminated clothing, towels, or bedding.
What to do: Treatment is usually done with medications such as permethrin or crotamiton, as recommended by a dermatologist. Wash all clothing, sheets, and towels that have been in direct contact with the skin in hot water.
9. Fungal skin infection
A fungal skin infection can be caused by fungi such as Malassezia furfur, Candida albicans, Trichophyton, Microsporum, or Epidermophyton.
It can cause itching, redness, and scaling, and it may affect any area of the body.
What to do: Follow a dermatologist’s treatment plan using antifungals in the form of cream or ointment, shampoo, lotions, or oral tablets.
10. Onychomycosis
Onychomycosis, or nail fungus, is an infection of the nail caused by fungi.
It can cause nail thickening, yellowish or whitish discoloration, separation of the nail from the skin, and buildup of debris under the nail.
What to do: Treatment should follow a dermatologist’s recommendation and may include antifungal creams or ointments, medicated nail lacquers, or oral antifungal tablets.
11. Herpes
Herpes is an infection of the skin or mucous membranes caused by the Herpes simplex virus. It can cause redness and small blisters that may itch or be painful.
Herpes simplex is more common on the lips (cold sores) or in the genital area (genital herpes).
What to do: See a dermatologist, who may recommend antiviral medications such as acyclovir, valacyclovir, or famciclovir for about 7 days. These medications help limit viral replication, support skin healing, and help control the appearance of new blisters and sores.
12. Chickenpox
Chickenpox, or varicella, is a skin infection caused by the varicella-zoster virus. It is more common in childhood but can also affect adults of any age.
It causes small blisters that may contain fluid and red spots over the body, along with intense itching that can lead to skin sores.
Varicella-zoster can cause shingles, which most often affects the chest and abdominal area.
What to do: Rest and use medications recommended by a dermatologist or pediatrician, such as acetaminophen for fever or anti-allergy medications in tablet form or topical ointments for itch relief.
Avoid contact with other people, because chickenpox is highly contagious and can spread through direct contact with blister fluid or through saliva droplets from coughing or sneezing.
13. Measles
Measles is a highly contagious skin infection caused by a virus in the Paramyxoviridae family (Morbillivirus).
Symptoms can include fever, persistent cough, runny nose, conjunctivitis, and small reddish spots that start near the scalp and then move downward, spreading over the body.
It spreads through inhaled respiratory droplets when an infected person coughs or sneezes.
What to do: Treatment is managed by a dermatologist or pediatrician to relieve symptoms, because the body can eliminate the virus naturally.
Rest, hydration, and light meals are usually recommended. Measles can be prevented with the MMR vaccine, which also protects against mumps and rubella and is part of routine childhood immunization schedules.
14. Hand-foot-and-mouth disease
Hand-foot-and-mouth disease is a highly contagious skin infection caused by the Coxsackie virus.
It is more common in children under 5 years old and can cause painful blisters on the hands and feet, sometimes in the groin or genital area, along with painful mouth sores and fever.
It can spread from person to person or through contaminated food or objects.
What to do: See a pediatrician, dermatologist, or primary care provider, who may recommend medications for fever, anti-inflammatory drugs, itch-relief medications, and topical treatments for mouth sores to help relieve symptoms.
15. Warts
Warts are an infection of the skin or mucous membranes caused by HPV.
They can appear as smooth, rough, flat, or raised lesions and may be skin-colored, pink, gray, yellowish, brown, or black.
They can occur anywhere on the body, including the vagina, labia majora, penile shaft, scrotum, or anal area, in which case they are called genital warts.
What to do: Treatment should be guided by a dermatologist and may include medications containing salicylic acid and/or lactic acid, cryotherapy, or laser surgery.
For genital warts, treatment should be guided by a gynecologist or urologist and may include topical treatments, application of acids to the skin, or procedures to remove the warts.
16. Acne
Acne (pimples) is a skin condition that occurs when hair follicles become clogged with oil or dead skin cells, which can promote bacterial overgrowth.
It can be associated with hormonal changes, stress, a high-fat diet, or the use of medications such as corticosteroids.
What to do: Treatment should follow a dermatologist’s recommendations and may include topical creams or, in some cases, oral antibiotics or oral retinoids. During pregnancy, oral retinoids should not be used because they can cause birth defects.
Read more about acne treatments, including oral and topical medications plus home remedies.