There is redness on the penis, but it is not painful or itchy.

Many people often develop erythema on their penis. Some of these erythema are normal and non-itchy, while others are itchy and painful. Based on the symptoms, it can be considered that it is due to poor development of the penis or excessive foreskin, which leads to blockage of urethral secretions and causes a necrosis and infection. Another possibility is local trauma leading to inflammation on the skin surface. However, inflammation usually causes pain and itching. If there are no such symptoms and the cause cannot be clearly determined, you need to go to the hospital for examination.

Causes

Physiological factors

Poor or abnormal development of the penis can lead to an unfavorable anatomical structure, prepuce hyperplasia and phimosis, which can cause the glans penis and urethra opening to be irritated by urine retained in the urethra opening and urine scale in the foreskin cavity, or foreskin incarceration, resulting in congestion, swelling, ischemia, necrosis, etc. of the glans penis, thereby reducing the anti-infection ability of the glans penis and urethra opening, making it easy to be infected by pathogens.

Local trauma

Normal glans penis and penile skin have strong resistance to normal flora living in the penile skin and certain pathogenic bacteria that infect the penile skin, so under normal physiological conditions, penile skin infectious diseases usually do not occur. However, if the glans penis or its skin is injured by squeezing, itching, intense masturbation, sexual intercourse, and oral sex, it may be conducive to pathogenic pathogens and conditional pathogens to infect penile tissues and cause penile inflammatory reactions.

Reduced body resistance

The occurrence of certain penile infections is often related to factors such as colds, diabetes, overwork, dysbacteriosis, tumors or the use of immunosuppressants, which lead to a decrease in the body's resistance or immune capacity. For example, colds or overwork can reduce the body's resistance, which can often cause the activation of latent herpes simplex virus (HSV) and the formation of recurrent infections; diabetic patients, tumor patients and patients treated with immunosuppressants are often prone to penile tissue infections caused by different species of Saccharomyces spp. due to reduced immunity; irregular use and abuse of antimicrobial drugs can cause urinary tract dysbacteriosis, which can lead to infection with certain resistant pathogens and conditional pathogens and cause inflammatory reactions of the glans penis or glans balanitis.

Clinical manifestations

Vulvitis is manifested by redness, swelling, pain, and itching of the glans penis and foreskin. Vulvitis is more common in men around 20-30 years old. The damage mainly occurs at the junction of the edge of the glans penis and the coronal sulcus and/or the frenulum. The damage is a papule of 1-3mm in size, and the damage is larger on both sides of the frenulum. The top of the papule is round and smooth, and some papules are hairy or filamentous. The papules are mostly unfused, and are densely arranged in one or more rows. They are obvious on the dorsal side of the glans penis and can partially or completely surround the glans penis. The color of the damage is mostly pearly white, a few are light red or skin-colored, and some may appear slightly red and swollen. There is no tenderness, no rupture, and the patient has no conscious symptoms. Histopathological examination of vulvitis shows hyperkeratosis, mild to moderate hyperplasia of the epidermis, normal basal layer, slight hyperplasia and density of collagen fibers in the dermis, varying degrees of hyperplasia and dilation of dermal papillary capillaries, a small amount of lymphocyte infiltration around, and no concave cells.