What Is That Bump on My Penis?

Non-Infectious and Infectious Causes

If you notice a rash or spot on your penis, your mind may immediately go the worst-case scenario and assume that its either penile cancer or a sexually transmitted infection (STI). More often than not, it will be something that is far less serious but a condition you will want to get checked out nevertheless.

Here are just some of the non-infectious and infectious causes your doctor may investigate.

causes of penile rash
Verywell / Emily Roberts

Non-Infectious Causes

A non-infectious penile skin condition is one that you cannot get it from or pass it to another person. While this shouldn't suggest that you can ignore it, a non-infectious skin condition tends to be less serious than an infectious one.

Inflamed Hair Follicles

In some cases, multiple tiny bumps beneath the skin of the scrotum or base of the shaft may be nothing more than inflamed hair follicles. While more irritating than problematic, the condition may be caused by harsh chemicals, abrasion, or an allergen your doctor can help identify.

Pearly Penile Papules

A similar condition called angiofibroma is characterized by dome-shaped or jagged bumps around the head (glans) of the penis. They are also known as pearly penile papules.

These bumps are more common in uncircumcised men. They are neither infectious nor require treatment (although some men will remove them for cosmetic purposes if they are especially pronounced).


Angiokeratomas are small red or blue spots that may appear only on the glans or extend to the scrotum, groin, thighs, and abdomen. The spots are not infectious and require no treatment unless they cause pain or bleeding. Treatment options include laser therapy or electrodesiccation.


Psoriasis is a non-infectious skin disorder that can sometimes develop on the penis, causing a red or salmon-colored patch with a white or silvery scales. It is an autoimmune disorder in which your immune system attacks skin cells on different parts of the body.

Psoriasis can often be treated with topical corticosteroids, which temper the immune response, or oral medications that treat psoriasis systemically.

Lichen Sclerosus 

Lichen sclerosus is an abnormal skin condition that affects around one of 300 men at some point in their lives. It causes a crinkled whitish (hypopigmented) lesion, usually around or under the glans. The cause is unknown but is believed to be triggered by an overactive immune system.

Lichen sclerosus lesions are often itchy and may lead to painful erections (priapism) or painful or difficult urination (dysuria). They can often be treated with topical corticosteroids but may require surgical removal if they are especially large and fail to respond to treatment.

Any persistent lichen sclerosis lesion should be monitored as the condition is linked to a 4% to 5% percent risk of cancer.

Lichen Planus

Lichen planus is a rare skin condition characterized by raised, flat, violet-colored bumps on the glans of the penis. The bumps sometimes have fine white streaks and a smooth surface. The lesions often appear in a ring or a line and may or may not be itchy.

Lichen planus can affect other parts of the body, especially the wrists, shins, and inside of the cheeks. The condition is not infectious and can usually be treated with topical corticosteroids. For reasons not entirely understood, lichen planus affects people with hepatitis C five times more often than people without.


Eczema is a chronic condition that causes the skin to become itchy, red, dry, and cracked.

All these noninfectious causes can cause scarring of the penis, especially when it is uncircumcised. This condition is called phimosis, in which the foreskin has difficult with retraction due to scarring. There can be redness, skin cracks, and tender sore areas when this happens to the penile skin.

Infectious Causes 

Infectious causes of penile skin conditions are most often sexually transmitted and may require medical intervention.

Human Papillomavirus (HPV)

Human papillomavirus (HPV) is a highly contagious STI characterized by the development of genital warts. It is passed through vaginal sex, anal sex, oral sex, or skin-to-skin sexual contact (such as frottage or mutual masturbation).

In men, HPV warts can develop on the penis, around the anus, in the throat, or be internalized in the rectum.

In most cases, an HPV infection will be spontaneously cleared by the immune system. In a small subset of individuals, the genital wart will persist and develop into cancer. Some strains of HPV are more carcinogenic than others.

Treatment may involve topical solutions to gradually remove the wart or in-office procedures to either cut away, freeze, or burn the wart. Men at an increased risk of cancer—most specifically gay or bisexual men with HPV—should consider an anal pap smear to test for cancer if they have or have previously experienced genital warts.

Primary Syphilis

Syphilis is an STI that can be contracted after contact with a syphilitic sore during sex. The sore is typically a circular, ulcerative lesion that does not cause pain, It may either be visible (on the penis or around the anus) or unseen (in the rectum, mouth, or throat).

The sore is one of the first symptoms of primary syphilis. If left untreated, it can progress months or years later to more serious forms the disease called secondary and tertiary syphilis.

Syphilis may be diagnosed with a blood test or biopsy of the skin lesion. Syphilis can be treated with a single dose of enzathine penicillin delivered intramuscularly (into a muscle, usually the buttocks).

 If syphilis spreads it can cause long term damage to the body, including the nervous system. Therefore, if you are diaqnosed with syphilis it is important to get treatment right away.

Genital Herpes

Genital herpes is an STI caused by the herpes simplex virus (HSV). The viral infection, related to cold sores, triggers the development of small blisters that break open into painful sores. The first herpes episode often causes severe pain and flu-like symptoms, while recurrent episodes tend to be milder.

The infection is transmitted by contact with a blister during the active phase of infection. In some cases, a cold sore can cause genital herpes as a result of oral sex.

Antiviral medications may reduce the risk of recurrence and lessen the severity of an active episode. Certain external factors like stress can also increase the risk of recurrence. If you have active herpes sores, it is important to avoid sex until the infection is fully resolved.

Molluscum Contagiosum

Molluscum contagiosum is a common viral disease that is easily passed through sexual contact. Besides direct skin-to-skin contact, the sharing of towels, face cloths, gym mats, and personal care items can also cause transmission. People with weakened immune systems, such as those with advanced HIV, are especially prone to infection.

Molluscum contagiosum is characterized by an outbreak of firm, dome-shaped bumps with a central depression. They can appear on the genitals and inner thighs, as well as the face, neck, armpits, arms, hands, and abdomen. While the bumps are typically painless, they may itch and turn from a fleshy to a bright red color when scratched.

The infection is usually self-limited, meaning it will eventually go away on its own. Some people may choose to have them removed to reduce the risk of transmission and/or for cosmetic purposes. Topical creams containing retinoids can sometimes help.

Penile Cancer

Penile cancer is a much less common cause of a penile skin disorder, affecting only around 2,080 American men a year. The initial precancerous tumor (called penile carcinoma in situ) is often red and raised with a velvety texture.

Almost 95% of all penile cancers are classified as squamous cell carcinomas. These tumors grow slowly and typically cause flat skin lesions on the glans or foreskin.

Verrucous carcinomas are also slow to develop and look rather like large warts. Penile melanoma is the most dangerous type, developing rapidly and causing purplish, brown, or black lesions.

The good news is that, when treated early, most penile cancers can be cured. If treatment is delayed, more aggressive interventions may be needed, including the partial or complete removal of the penis (penectomy).

A Word From Verywell

These are only a few of the possible causes of a penile rash or growth. What these conditions should illustrate is that self-diagnosis is never a good idea and that early intervention not only prevents serious complications but may reduce the risk of transmission to others.

If the thought of discussing your penis with your doctor makes you uneasy, it often helps to call your doctor first to "break the ice." Whatever you do, do not let embarrassment get in the way of seeking the diagnosis you need.

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