Key Takeaways
- Skin infections occur when bacteria, viruses, fungi, or parasites affect the skin.
- Common signs include redness, swelling, warmth, pain, pus, blisters, fever, or skin that worsens instead of healing.
- Some skin infections remain mild, while others spread to deeper tissues or the bloodstream and can become serious.
- Treatment depends on the cause and severity, and many infections are treatable when identified early.
- Medical evaluation is recommended if symptoms worsen, spread, or are accompanied by fever or severe pain.
Overview
Skin infections occur when bacteria, viruses, fungi, or parasites affect the skin. They can range from mild and localized to serious conditions that spread to deeper tissues or the bloodstream. Most skin infections are treatable, especially when identified early, but some require prompt medical evaluation.
This guide explains what has been medically verified about skin infections, how they commonly appear, and when to seek care. Any areas where strong evidence is lacking are clearly labeled.
Common Signs and Symptoms
Verified medical sources consistently show that skin infections often involve one or more of the following:
- Redness or discoloration of the skin
- Swelling or firmness
- Warmth compared to surrounding skin
- Pain or tenderness
- Pus, drainage, yellow crusts, or pus-filled bumps
- Blisters or skin lesions
- Fever, chills, or a general feeling of being unwell
- Skin that does not improve or continues to worsen
Some infections remain mild, while others progress or spread if not treated.
Signs an Infection May Be Serious or Spreading
Medical evidence supports that a skin infection may be more serious if you notice:
- Redness that spreads rapidly
- Increasing swelling, warmth, or pain
- Fever or chills
- Pus, blisters, or areas of skin breakdown
- Darkened or discolored skin that may signal tissue damage
- Severe pain, especially when accompanied by systemic symptoms
Skin infections can, in some cases, spread beyond the skin into deeper tissues or the bloodstream and lead to life-threatening complications such as sepsis.
Common Causes
Verified causes of skin infections include:
- Bacteria
- Viruses
- Fungi
- Parasites
These organisms may enter through:
- Cuts, scratches, wounds, or surgical sites
- Insect bites or stings
- Damaged or cracked skin
- Moist environments that allow organisms to multiply
Some bacteria and fungi normally live on the skin without causing harm but can lead to infection if they multiply excessively or enter deeper layers of skin.
Types of Skin Infections
Bacterial Skin Infections
Common features include:
- Red, swollen, warm skin
- Pain or tenderness
- Pus or yellow crusting
- Fever in more severe cases
Examples supported by evidence include impetigo, cellulitis, folliculitis, boils, and MRSA infections.
Viral Skin Infections
These often cause:
- Blisters, bumps, or sores
- Tingling, burning, or itching before blisters appear
- Localized pain
Examples include cold sores (herpes simplex), shingles, and warts. Many viral skin infections spread through direct skin contact.
Fungal Skin Infections
Typically affect warm, moist areas of the body and may cause:
- Itchy, scaly patches
- Redness with defined borders
- Peeling or cracking skin
- Ring-shaped rashes in some cases
Examples include athlete’s foot, jock itch, ringworm, and yeast infections.
Parasitic Skin Infections
These are caused by organisms living on or in the skin. Verified features include:
- Intense itching
- Rashes or small bumps
Scabies is a well-documented example.
Who Is at Higher Risk?
Evidence shows higher risk in people who:
- Have diabetes
- Have poor circulation
- Have a weakened immune system
- Are older adults
- Have certain skin diseases
- Live in crowded or close-contact settings
How Skin Infections Are Diagnosed
Clinicians may:
- Examine the affected skin
- Ask about symptoms and progression
- Take swabs, scrapings, or fluid samples for laboratory testing
Testing helps determine the cause and guide treatment.
Treatment Options
Treatment depends on the cause and severity. Verified options include:
- Antibiotics for bacterial infections
- Antivirals for certain viral infections
- Antifungals for fungal infections
- Antiparasitic medications for parasitic infections
- Supportive care to reduce symptoms
Some mild infections may improve with over-the-counter treatments, while more severe cases may require prescription medication or hospital care.
When to See a Doctor
You should seek medical care if you have:
- A skin infection that does not improve or worsens
- Rapidly spreading redness or swelling
- Fever or chills
- Pus-filled blisters or open sores
- Severe pain or significant skin discoloration
There is insufficient high-quality evidence to state that infections on specific body areas (such as the face, eyes, or genitals) always require emergency care, but medical evaluation is advised if symptoms are severe or worsening.
Frequently Asked Questions
How can I tell if my skin is infected?
Common verified signs include redness, swelling, warmth, pain, pus, blisters, and skin that worsens instead of healing.
How do you know if a skin infection is serious?
Evidence supports concern when symptoms spread, pain increases, fever develops, or the skin shows signs of breakdown or discoloration.
Can skin infections spread?
Yes. Some skin infections can spread to deeper tissues or the bloodstream and may lead to serious complications.
Are skin infections contagious?
Some are, depending on the cause. Bacterial, viral, and parasitic infections may spread through direct contact or shared items.
How long does a skin infection last?
There is no single duration. Healing depends on the cause, severity, and treatment. High-quality evidence does not support a universal timeline.
Can you treat a skin infection at home?
Mild infections may respond to over-the-counter care, but worsening or persistent symptoms require medical evaluation.
What causes blisters on the skin?
Blisters can occur with infections, but they can also result from other conditions.
There is no high-quality evidence supporting a single cause without medical evaluation.
When should I go to the emergency room?
Emergency care is required for signs of sepsis or severe systemic illness. For other cases, evidence supports seeing a clinician if symptoms worsen or do not improve.
APA Reference List
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Centers for Disease Control and Prevention. (2024, April 24). Symptoms of ringworm and fungal nail infections. https://www.cdc.gov/ringworm/signs-symptoms/index.html
Centers for Disease Control and Prevention. (2025, June 27). Preventing methicillin-resistant Staphylococcus aureus (MRSA). https://www.cdc.gov/mrsa/prevention/index.html
Centers for Disease Control and Prevention. (n.d.). Shingles vaccine recommendations. https://www.cdc.gov/shingles/hcp/vaccine-considerations/index.html
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Mayo Clinic Staff. (n.d.). Folliculitis: Symptoms and causes. https://www.mayoclinic.org/diseases-conditions/folliculitis/symptoms-causes/syc-20361634
Mayo Clinic Staff. (n.d.). HPV infection: Symptoms and causes. https://www.mayoclinic.org/diseases-conditions/hpv-infection/symptoms-causes/syc-20351596
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MSD Manuals. (n.d.). Candidiasis (yeast infection). https://www.msdmanuals.com/home/skin-disorders/fungal-skin-infections/candidiasis-yeast-infection
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