A painful erection can result from several different conditions, ranging from a prolonged erection that traps blood in the penis (priapism) to scar tissue buildup, infections, foreskin problems, or acute injury. Some causes resolve on their own, while others require urgent medical attention within hours to prevent permanent damage. Understanding the most likely causes can help you figure out what you’re dealing with and how seriously to take it.
Priapism: When an Erection Won’t Go Away
Priapism is an erection that persists for hours without sexual stimulation, and the most common form is intensely painful. It happens when blood flows into the penis but can’t drain back out, leaving the tissue starved of oxygen. The trapped blood becomes dark, acidotic, and oxygen-depleted, which is what produces the pain. An erection lasting more than four hours is classified as a medical emergency.
There are two types. Ischemic (low-flow) priapism, the more common and dangerous kind, involves a failure of the veins to let blood exit. It is generally painful, though the pain can paradoxically fade in very prolonged episodes as nerve tissue becomes damaged. Non-ischemic (high-flow) priapism results from uncontrolled arterial inflow, often after an injury that creates an abnormal connection between an artery and the erectile tissue. This type is generally not painful because the tissue stays oxygenated.
If ischemic priapism lasts beyond 24 hours, it can cause permanent scarring inside the erectile chambers and loss of penile length. Cases lasting more than 36 hours may require surgical placement of a penile implant. Treatment in the emergency room typically involves draining blood from the penis and injecting a medication that constricts blood vessels, allowing the erection to resolve. The goal is to restore normal blood flow before the tissue is irreversibly damaged.
Medications That Can Trigger Priapism
Several classes of drugs are known to cause priapism. Erectile dysfunction medications, including both injectable treatments and oral pills like sildenafil and tadalafil, are well-documented triggers. Certain psychiatric medications also carry risk: all atypical antipsychotics can cause priapism, and trazodone, an antidepressant often prescribed as a sleep aid, is another known cause. Some blood pressure medications, particularly alpha-blockers like prazosin and tamsulosin, have also been linked to prolonged erections.
Peyronie’s Disease: Scar Tissue Inside the Penis
Peyronie’s disease develops when repeated small injuries to the inner lining of the penis heal with scar tissue instead of flexible tissue. This scar tissue, called plaque, forms along the tough membrane that surrounds the erectile chambers. As the plaque hardens, it pulls on the surrounding tissue and creates a noticeable curve in the erect penis.
The condition has two phases. During the acute phase, which can last 12 to 18 months, the plaque is actively forming. This is when pain during erections is most common, because the scar tissue is inflamed and still changing. The penis may also be gradually curving more during this time. In the chronic phase, the plaque stabilizes, the curvature stops progressing, and pain typically fades. Prevalence estimates vary widely. A large survey found that about 0.7% of men had definitive Peyronie’s disease, but roughly 11% had probable signs of the condition, suggesting it is significantly underdiagnosed.
Infections and Inflammation
Infections in the urinary or reproductive tract can make erections painful even when the erection itself is normal. Prostatitis, or inflammation of the prostate gland, is one of the more common culprits. Bacterial prostatitis occurs when bacteria travel from the urethra into the prostate, causing swelling and tenderness. The acute form comes on suddenly with severe symptoms, while chronic bacterial prostatitis develops slowly and can persist for years.
A third form, chronic pelvic pain syndrome, produces similar symptoms without a clear bacterial cause. Researchers believe a microorganism that isn’t a standard bacterium may be responsible. All forms of prostatitis can cause pain in the penis and painful ejaculation, which many men experience as pain during or immediately after an erection. Urethritis, an infection of the urethra itself, can similarly cause burning or aching that worsens when the tissue becomes engorged during arousal.
Foreskin Problems: Phimosis and Paraphimosis
In uncircumcised men, a foreskin that is too tight to retract over the head of the penis (phimosis) can cause pain during erections as the expanding tissue strains against the constriction. This is often manageable with gentle stretching over several weeks, and more stubborn cases may benefit from prescription steroid creams or minor surgical correction.
Paraphimosis is the more urgent version. It happens when the foreskin is pulled back behind the head of the penis and gets stuck there. The retracted foreskin acts like a tourniquet, causing the head of the penis to swell, which makes the constriction worse in a vicious cycle. Paraphimosis is treated as an emergency because the constriction can quickly cut off blood supply and cause tissue death if not resolved.
Penile Fracture
A penile fracture is a rupture of the tough outer membrane of the penis, usually during vigorous sexual activity when the erect penis bends abnormally. Despite the name, there is no bone involved. The membrane that keeps blood contained during an erection tears, and the result is unmistakable: a popping or cracking sound, immediate loss of the erection, and intense pain. Bruising and swelling develop rapidly from blood leaking under the skin, and some men notice blood in their urine or at the tip of the penis.
This is a surgical emergency. The tear needs to be repaired quickly to prevent long-term scarring, curvature, or erectile dysfunction. The pain may subside on its own after the initial injury, but that doesn’t mean the damage is minor. Delaying treatment significantly worsens outcomes.
Less Common Causes
Sickle cell disease is one of the leading non-drug causes of priapism, particularly in younger men and boys. The misshapen red blood cells can clog the small veins that drain the penis, trapping blood in the same way as ischemic priapism. Some men also experience painful erections from nerve conditions, pelvic injuries, or spinal cord problems that disrupt the normal signals controlling blood flow into and out of the penis.
Occasionally, pain during erections stems from something as straightforward as a skin condition on the penis, such as a tight scar from a previous procedure, an allergic reaction, or a localized infection. These tend to cause surface-level pain rather than the deep aching associated with conditions like priapism or prostatitis.