Swollen Penis: Foreskin, Shaft, Urethra Causes

A swollen penis can occur due to many causes other than a normal erection. The abnormal swelling may be due to an allergy or caused by an infection that leads to balanitis (inflammation of the penis head), posthitis (inflammation of the foreskin), or urethritis (inflammation of the urethra).

Injuries can also lead to swelling, including a penile fracture or an abnormal curve called Peyronie's disease. There are also rare but serious causes like penile cancer and paraphimosis (a medical emergency in which the foreskin becomes trapped behind the head of the penis).

This article looks at nine possible causes of a swollen penis. It also describes ways to treat or manage the condition and when it is time to see a specialist known as a urologist.

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For the purpose of this article, "male" refers to people born with penises, and "female" refers to people born with vaginas, irrespective of the gender or genders they identify with.

The penis may be abnormally swollen for many different reasons. This includes conditions that affect different parts of the penis known as:

The causes can range from skin reactions and injuries to infections (including sexually transmitted infections) and even cancer.

Certain substances can cause the penis to swell when they come into contact with the skin. This is known as contact dermatitis. Types include allergic contact dermatitis caused by an allergic skin reaction, and irritant contact dermatitis caused by substances that irritate the skin.

While both can cause red, swollen skin, allergic contact dermatitis often causes a delayed reaction, while irritant contact dermatitis tends to be immediate. Other symptoms include a rash, skin dryness, itching, cracking, burning, or flaking.

Here are some allergens and irritants that can cause a swollen penis.

Latex (such as latex condoms)

Nickel (such as nickel cock rings or genital piercings)

Scented soaps and bubble bath

Perfumes and body sprays

Topical anesthetics in desensitizing gels

Spermicides (like nonoxynol-9 found in certain condoms and personal lubricants)

Soaps

Laundry detergent and bleach

Body or massage oils

Alcohol-based cleansers

Hair dyes

Topical antibiotic or antifungals use to treat penile infections

Prolonged exposure to moisture (such as caused by bladder leakage)

Any injury to the penis can cause inflammation and swelling. Inflammation is a protective immune response that causes blood vessels to widen (dilate) to increase circulation and promote healing. The dilation, in turn, causes tissues to swell.

In addition to swelling, injuries to the penis can cause contusions (bruising) and hematomas (the pooling of blood under the skin).

Severe injuries can sometimes cause a penile fracture. This is when the membrane surrounding the inner shaft of the penis (called the tunica albuginea) ruptures. This can occur during aggressive sex or a sex accident (such as falling onto your erection).

Even minor traumas can cause cumulative damage over time, leading to a condition called Peyronie's disease (PD), in which the penis suddenly develops an abnormal curve. While PD does not cause overt swelling, it can cause a lump at the site of the bend. People over 40 are most commonly affected.

A penile fracture is a medical emergency that can lead to permanent deformity and erectile dysfunction if left untreated.

Go to your nearest emergency room if a penis injury occurs during sex causes:

Lichen sclerosus is a chronic inflammatory skin disease that can cause itching and pain. While it can affect any part of the body, it most often involves the genitals and the skin around them.

Lichen sclerosus is more common in males who are uncircumcised (who have a foreskin) and/or have urinary incontinence (the loss of bladder control). The cause of lichen sclerosus is unknown but is thought to involve a combination of factors, including genetics, an overactive immune system, and previous skin damage.

While lichen sclerosus typically causes the tightening and hardening of the foreskin and glans, it can also cause swelling due to the build-up of fluids (known as edema). Other symptoms include painful urination, painful erections, and dribbling.

Balanitis is inflammation of the head of the penis. It affects around 11% of adults and 4% of children with penises, primarily those with foreskins. It can occur at any age but is most common after age 40.

Poor hygiene plays a central role. In people with foreskins, the accumulation of smegma (a curd-like mixture of dead skin cells and body oils) can cause inflammation under the foreskin, leading to redness, swelling, pain, and itching.

When the glans and foreskin are both affected, it is called balanoposthitis. The swelling of the foreskin alone is referred to as posthitis.

With treatment and proper skin care, balanitis can clear in five days. If left untreated, balanitis can lead to complications like phimosis and paraphimosis (to be discussed).

Priapism is an erection that lasts more than four hours in the absence of sexual stimulation. The majority of cases are caused by ischemia (the restriction of blood flow) that doesn't allow an erection to go down. In such cases, the penis shaft will remain swollen but the glans will be soft.

Causes of priapism include:

An erection that lasts for more than four hours can severely deprive the penis of oxygen, gradually destroying tissues and nerves. If left untreated, priapism can lead to erectile dysfunction.

Phimosis is a condition in uncircumcised males in which the foreskin cannot be pulled back over the head of the penis.

Phimosis is usually a painless condition caused by the failure of the foreskin to loosen during sexual development. Even so, the tightness can sometimes cause painful erections and interfere with urination.

Phimosis can also be caused by infections (such as balanitis) or diseases affecting the glans and foreskin (like lichen sclerosus). In such cases, a person may experience pain, swelling, and redness of the glans and foreskin.

Paraphimosis is when a foreskin gets "stuck" behind the head of the penis after it has been pulled back. It is considered a medical emergency as the trapped foreskin can cut off the blood supply. If the foreskin cannot be restored to its normal position, the loss of blood flow can cause severe edema and tissue death (necrosis).

Paraphimosis typically causes pain and swelling along with the dark purplish discoloration of the glans. However, some people may experience little pain until the condition turns severe.

Paraphimosis is always treated as a medical emergency regardless of whether the pain is severe or not. While rare, the condition may cause extensive tissue death and require a partial or complete amputation of the penis.

Urethritis is the inflammation of the urethra. In males, the urethra runs from the bladder to the end of the penis.

Urethritis typically causes urination problems such as frequent urination, pain with urination, and frequent nighttime urination. It can also cause redness and swelling of the meatus.

When urethritis is accompanied by balanitis, it is most often the result of a sexually transmitted infection (STI) like:

A rare cause of a swollen penis is penile cancer. Penile cancer can affect anyone with a penis, but uncircumcised males with a history of recurrent balanitis are at an increased risk.

Penile cancer is closely linked to the human papillomavirus (HPV). Early symptoms include penile lesions, scaling, redness, and bumps. As the malignancy progresses, it can cause the thickening and swelling of the glans and foreskin accompanied by an open, spreading sore.

Penile cancer is rare, affecting fewer than 1 of every 100,000 males in the United States and accounting for less than 1% of all cancers in males.

There are times when a swollen penis can be treated or managed at home. Certain at-home treatments can help ease symptoms and even resolve the condition without medical treatment.

Examples include:

Certain conditions—like penile fracture, priapism, paraphimosis, and penile cancer—need to be seen immediately by a healthcare provider. Others may require treatment to slow disease progression (such as lichen sclerosus) or clear underlying infection (such as urethritis).

Even milder cases of contact dermatitis, balanitis, and phimosis may benefit from treatment if the symptoms are persistent, recurrent, or worsening.

It is important to see a healthcare provider if your swollen penis:

Penile swelling is treated by resolving the underlying condition. This may involve the use of over-the-counter or pharmaceutical drugs as well as specialist procedures, including surgery.

It's best to discuss your symptoms with a healthcare provider before using OTC medications to ensure the drug is appropriate for the condition. Some of the OTC drugs that can ease penile swelling and related symptoms are:

Prescription drugs used to treat conditions like balanitis, lichen sclerosus, phimosis, and urethritis include:

Specialist procedures are generally considered when symptoms are severe or conservative treatments fail to provide relief on their own. Options include:

An erection is a natural physiological response to sexual stimulation that causes the penis to achieve a hardness suitable for sexual intercourse. But there are times when an erection can occur abnormally and be unwanted, generating significant distress and anxiety.

One example is persistent genital arousal disorder (PGAD), commonly associated with females but increasingly seen in males. PGAD causes spontaneous and unwanted genital arousal that is not relieved by orgasm or requires multiple orgasms over hours or days for the aroused state to subside.

PGAD is poorly understood but is thought to be caused by the dysfunction of the pudendal nerve that provides sensations to the genitals.

Another related condition called hard-flaccid syndrome (HFS) is characterized by a constantly semi-rigid penis. People with HFS have a lack of penile sensitivity and need excessive sexual stimulation to achieve an erection. When ejaculation occurs, it is often painful.

Most people with HFS report that symptoms started after a sexual injury at the base of the penis. Commonly cited causes include the aggressive use of vacuum pumps, jelqing, or rough sex.

Neither PGAD nor HFS is well understood, and no standard treatments exist. While various medical and surgical treatments are being explored, the bigger concern may be the general reluctance of males to report symptoms of sexual dysfunction compared to females.

Given the negative impact that sexual dysfunction can have on a person's well-being, it is important to reach out to urologists with knowledge about conditions like PGAD and HFS. They will know best which treatment options are available and may even be able to refer you to clinical trials.

Penile swelling is not a normal situation, and you will generally want to avoid sex until you've at least found out what is causing it.

While certain chronic (long-lasting) conditions like phimosis and lichen sclerosis don't necessarily exclude you from having sex, they may warrant a break if symptoms are getting worse or new symptoms develop. These symptoms can often be triggered by a co-occurring acute (sudden, severe) infection.

With acute conditions like balanitis and urethritis, sex should not be resumed until the infection is treated and cleared, usually within five to 10 days. Even if an STI is not involved, you can still pass harmful bacteria to a female partner and cause bacterial vaginosis (BV).

If an STI is involved, you need to avoid sex until the infection is cleared (and advise your partner of the diagnosis so they can get treated, too). With an STI like gonorrhea, you need to wait seven days after completing treatment before having sex. To avoid reinfection, wear a condom.

If you've experienced paraphimosis or have painful erections due to phimosis, you need to take care when engaging in sex. Use plenty of lubrication and consider wearing a condom to stabilize the foreskin and prevent it from slipping behind the head of the penis.

Persistent swelling of the head, foreskin, or shaft of the penis is never considered normal, especially if it causes pain, interferes with sex, and has signs of an infection.

A swollen penis can be caused by an injury, infection, allergy, or irritant. People with foreskins are vulnerable to balanitis (inflammation of the penis head), posthitis (inflammation of the foreskin), phimosis (a non-retractable foreskin), and lichen sclerosis (a chronic inflammatory skin condition).

Some causes are medical emergencies, including penile fractures, priapism (an abnormally prolonged erection), and paraphimosis (the trapping of the foreskin behind the head of the penis). A rare but serious cause of a swollen penis is advanced penile cancer.

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By James Myhre & Dennis Sifris, MDDennis Sifris, MD, is an HIV specialist and Medical Director of LifeSense Disease Management. James Myhre is an American journalist and HIV educator.