Balanitis - Causes

The causes of balanitis include the build up of a substance called smegma, fungal infections, and sexually transmitted infections (STIs).

Smegma

In most cases, balanitis occurs when the skin is irritated by the build up of a smelly, cheesy-looking substance called smegma.

Smegma is a natural lubricant that keeps the penis moist. It's found on the head of the penis and under the foreskin.

In young boys, smegma may build up because it can be difficult to fully retract the foreskin at this age. This makes it hard to keep the penis clean.

A build up of smegma can also lead to balanitis in uncircumcised men if the penis is not kept clean.

Other causes

Other causes of balanitis include:

• fungal infection (thrush) 
• bacterial infection – streptococcal bacteria is the most common type of bacteria to cause balanitis
• an allergic reaction or skin irritation – caused by an adverse skin reaction to certain substances, such as a bubble bath, or soap (the medical term for this type of skin reaction is contact dermatitis)
• an underlying skin condition, such as atopic eczema, or psoriasis (see below)
• in boys, repeatedly playing with their foreskin

Additional causes of balanitis in men include:

• having unprotected sex with a woman who has thrush
• sexually transmitted infections (STIs), such as genital herpes, chlamydia, gonorrhoea and syphilis
• irritation caused by the latex used in condoms

A number of other skin conditions are known to cause symptoms of balanitis in men, including:

• lichen planus – a non-infectious, itchy rash affecting a number of areas of the body
• lichen sclerosus – a skin condition affecting the skin around the genitals and anus
• Zoon's balanitis – a rare condition affecting middle-aged men and causes the head of the penis to become red, shiny and itchy
• circinate balanitis – a type of psoriasis that sometimes affects men with reactive arthritis 

If all causes of balanitis have been ruled out, you may have non-specific balanoposthitis. This is when the foreskin and the surface of the glans are inflamed, red and swollen, making it painful and difficult to pass urine. Balanoposthitis is usually treated with antibiotics, but in very severe cases circumcision may be required.