Sexually Transmitted Infections of the Penis: Genital Herpes & HPV

Genital Herpes

Genital herpes is caused by the herpes simplex virus (HSV), predominantly by HSV-2, but in a growing share of cases also by HSV-1 – the pathogen responsible for cold sores – which can be transmitted to the genital area through oral sex. The infection is among the most common sexually transmitted diseases; WHO estimates put the number of people infected with HSV-2 worldwide at over 500 million.

The initial infection is often symptomatic and typically presents as painful, fluid-filled blisters on the penis, scrotum, anus, or adjacent skin areas, accompanied by redness, burning, and itching. General symptoms such as fever and swollen lymph nodes in the groin are not uncommon during the primary infection. After the blisters heal, the virus persists lifelong in the sensory ganglia and can be reactivated at any time – encouraged by stress, immunosuppression, fever, or UV exposure. Recurrences are usually shorter and milder than the initial outbreak; some people affected have only rare flare-ups, others more frequent ones.

Of clinical importance is asymptomatic viral shedding: the virus can be transmitted even without visible lesions, which makes prevention more difficult. Condoms reduce the risk of transmission but do not provide complete protection, since viral shedding also occurs on areas of skin that are not covered.

Genital herpes cannot be cured; treatment is carried out with antiviral medications from the nucleoside analogue class – aciclovir, valaciclovir, or famciclovir – which shorten the duration and severity of episodes and can be used as long-term suppressive therapy in cases of frequent recurrences. At the first symptoms, or when there is reasonable suspicion of infection, medical advice should be sought promptly.

HPV – Human Papillomavirus

Human papillomaviruses (HPV) are a large, heterogeneous group of more than 200 virus types, of which about 40 can affect the mucous membranes and skin of the anogenital area. HPV is the most common sexually transmitted infection of all; most sexually active people become infected at least once during their lifetime, often without knowing it.

Clinically, a distinction is made between low-risk types – primarily HPV 6 and 11 – which cause benign genital warts (condylomata acuminata), and high-risk types – above all HPV 16 and 18 – which do not produce immediate symptoms but can cause precancerous lesions and carcinomas over the long term. High-risk HPV is the main cause of cervical cancer as well as a significant share of anal, oropharyngeal, and penile cancers.

On the penis, HPV can affect any area – the glans, the shaft, the foreskin, the scrotum, and occasionally the urethral opening. Most infections heal spontaneously through the immune system, particularly in younger, immunocompetent men. If infections persist, low-risk types can lead to condylomata acuminata: soft, skin-coloured to reddish growths that appear singly or in cauliflower-like clusters and occasionally itch or burn, though they are rarely painful. High-risk types on the penis are usually asymptomatic but can lead to penile cancer over the course of years.

Diagnosis is made clinically through urological examination, supplemented where necessary by magnified inspection (dermoscopy), swabs for HPV DNA detection, or histological confirmation in unclear lesions. A blood test is not suitable for detecting HPV. Asymptomatic infections generally do not require treatment. Visible genital warts can be treated with topical immunomodulators (imiquimod), cryotherapy, laser ablation, or surgical removal; recurrences are possible and should be followed up.

The most effective protection against HPV is vaccination. The nonavalent vaccine available in Germany (Gardasil 9) protects against the nine most common HPV types, including the most important high-risk and low-risk types. The German Standing Committee on Vaccination (STIKO) recommends vaccination for girls and boys between the ages of 9 and 14; catch-up vaccination up to age 26 is also advisable. Since the introduction of vaccination programmes, a marked decline in HPV-associated diseases – cervical cancer in particular – has been measurable among vaccinated birth cohorts.

Condoms offer partial protection but do not cover all potentially infectious areas of skin. If visible changes appear in the genital area, sexual activity should be avoided and medical evaluation should be sought.