Bacteria, fungi, and viruses can all cause infections of the penis. Penis infections can range from mild and easily treatable conditions to severe or chronic illnesses.

In this article, we discuss the causes, symptoms, and treatments of different penis infections. We also provide guidance on when to seek medical attention.

Balanitis refers to inflammation of the head of the penis, known as the glans. Posthitis describes inflammation of the foreskin or the prepuce. Balanoposthitis is when balanitis and posthitis both occur.

According to a 2020 article, balanitis is a common condition that affects between 3–11% of males, while balanoposthitis occurs in 6% of people with uncircumcised penises.

Typically, these conditions result from irritation, trauma, or infection. Infectious causes of balanitis include:

Penile yeast infection

A type of fungus called Candida triggers yeast infections. Candida albicans (C. albicans) is the most common Candida species. Other names for a penile yeast infection include candida balanitis, candidiasis, and thrush.

Streptococcal infection

Streptococcus, or strep, is a group of bacteria. There are two main types: alpha (α)-hemolytic streptococci and beta (β)-hemolytic streptococci. Beta-hemolytic streptococci can further be split into two groups: group A and group B streptococci.

According to a 2018 book, the Streptococcus species are the most common bacterial cause of balanitis.

Diagnosing balanitis, posthitis, and balanoposthitis

A doctor can diagnose balanitis with a physical examination. They will look for swelling and redness of the glans, foreskin, or both.

They can then order the following diagnostic tests to identify the underlying infection:

  • swab culture from the glans
  • urinalysis
  • blood test

Treatments for balanitis, posthitis, and balanoposthitis

Treatment for balanitis depends on the underlying cause.

A doctor will treat a penile yeast infection with a topical antifungal, such as miconazole, imidazole, and clotrimazole. They may prescribe an oral antifungal, called fluconazole, if there are severe yeast infections throughout the body.

Oral antibiotics, such as erythromycin, penicillin, and ampicillin, are effective for treating Staphylococcus infections. A doctor may combine oral and topical antibiotics, such as mupirocin.

Pthiriasis refers to a Phthirus pubis or pubic lice infestation. Pubic lice are parasitic insects that live on coarse body hair, such as pubic hair. Pthiriasis spreads through sexual contact or contact with infested clothing, towels, or bedding.

Symptoms of pthiriasis include:

  • persistent or severe itching in the genital region
  • red, swollen, tender skin
  • visible lice eggs, larvae, or adult lice
  • black flecks in underwear
  • spots of dried blood on the skin on or near the groin

Diagnosing pthiriasis

A doctor can diagnose pthiriasis by removing adult lice or lice eggs from pubic hair. They may examine a hair sample under a microscope and search for lice eggs and other signs of parasitic infestation.

Treating pthiriasis

A doctor can physically remove lice and lice eggs if the infestation is relatively mild.

Over-the-counter (OTC) ointments that contain permethrin, pyrethrins, or piperonyl butoxide are effective against pubic lice infestations. A doctor may prescribe a medicated shampoo called lindane that kills adult lice and their eggs.

People should also wash their clothing, bedding, and towels with hot water and detergent. Drying laundry with high heat also helps kill lice and eggs.

Sexually transmitted infections (STIs) refer to infections that pass between people through sexual contact. Not all STIs lead to noticeable symptoms in males. When symptoms do occur, they can include:

  • pain or burning during urination or ejaculation
  • a frequent need to urinate
  • abnormal or foul-smelling discharge from the penis
  • swelling in one or both testicles
  • painful blisters or sores
  • fever
  • sore throat
  • muscle aches
  • swollen lymph nodes

Examples of STIs include:

Diagnosing STIs

Healthcare providers diagnose STIs with the following methods:

  • urinalysis
  • blood tests
  • cell cultures of samples collected from open sores or discharge

Treatments for STIs

Treatment options vary depending on the type of STI.

Chlamydia, gonorrhea, and syphilis are bacterial infections that usually require a single dose medicine or a 7-day course of antibiotics. People should complete the entire course of prescribed antibiotics, even if their symptoms resolve within a few days. Doing this helps prevent recurring infections.

Certain viral STIs, such as hepatitis B, HIV, HPV, and herpes, have no cure. Treatment focuses on managing symptoms and preventing future outbreaks. Antiviral medications can help fight the virus and slow the disease progression.

HPV warts may resolve on their own without medical treatment. However, OTC ointments that contain salicylic acid may help remove warts.

A doctor may recommend one or more of the following treatments to remove genital warts:

  • cryotherapy
  • laser therapy
  • surgical removal
  • prescription medication, including podofilox or podophyllin

A person should see their doctor if they develop symptoms of a penis infection. These can include:

  • fever or chills
  • swelling, redness, or warmth of the foreskin or the head of the penis
  • pain or itching on or near the genitals
  • ulcers or raised patches of skin
  • unusual discharge from the urethral opening
  • foul-smelling pus under the foreskin

Penis infections can lead to painful symptoms that can disrupt a person’s daily life. People should see a doctor if they develop signs of a penis infection, such as redness, swelling, itching, or sores in the genital area.

Sexually active people should also attend regular medical screenings for STIs, as many of them cause no noticeable symptoms in the early stages of infection.