Types of Genital Herpes Infections

First clinical episode refers to the initial symptomatic occurrence of herpes. The first clinical episode can be the result of a primary or non-primary infection with herpes type 1 or herpes type 2, or it can occur following an asymptomatic primary HSV-2 infection.

• Primary infection is defined as the first infection ever with either HSV-1 or HSV-2. No serum antibody is present when symptoms appear. The disease is more severe than in recurrent disease.
• Non-primary infection is defined as newly acquired infection with HSV-1 or HSV-2 in an individual previously seropositive to the other viral type. Manifestations tend to be milder than those of primary infection. Cross-reacting antibody is present initially and may rise in convalescence.
• Recurrence. Twenty-five percent of patients with first clinical episode of HSV-2 have had a prior asymptomatic primary infection. Type-specific antibody is present when the patient presents and the severity of the episode is comparable to a recurrence.

The first clinical episode of a primary HSV infection is characterized by the occurrence of numerous bilateral painful genital lesions. Lesions last an average of 11-12 days (full re-epithelialization takes an average of 17-20 days). The lesions progress as follows:

papules --> vesicles --> pustules --> ulcers --> crusts --> healed

The median duration of viral shedding (from the onset of lesions to the last positive culture) is ~12 days, and correlates well with the mean time from the onset of vesicles to crusting

Systemic symptoms include fever, headache, malaise, and myalgia. Systemic symptoms peak within 3-4 days of onset of lesions and recede over the next 3-4 days.

Local symptoms include pain, itching, dysuria, vaginal or urethral discharge, and tender inguinal adenopathy.

Primary HSV cervicitis is likely and may manifest as a mucopurulent cervicitis, or be asymptomatic. In most cases, the cervix appears abnormal to inspection with ulcerative lesions, erythema, or friability.

Herpes proctitis may occur, manifesting with pain, discharge, tenesmus, constipation with or without symptoms of autonomic dysfunction, and severe ulceration on anoscopy.
Urethritis may occur and may cause a clear mucoid discharge.

Recurrent symptomatic infection is defined as infection in which the antibody is present when symptoms appear, although the patient may not be aware of previous episodes. Generally, there is no or little change in antibody titer in convalescence. Disease is usually mild and short in duration.

Recurrent symptomatic infection is characterized by illness lasting 5-10 days. Prodromal symptoms (localized tingling, irritation), beginning 12-24 hours before lesions, occur in approximately 50% of persons. Systemic symptoms usually do not occur.

Symptom duration is shorter than in primary infection. Duration of genital lesions is approximately 4-6 days; average duration of viral shedding is 4 days. Lesions tend to be unilateral, and symptoms tend to be less severe.

The average number of recurrences is 2-6 per year, but the number of recurrences is highly variable. HSV-2 primary infection is more likely to recur than HSV-1 primary infection, and recurrences are more frequent if the primary episode is prolonged (i.e., greater than 30 days).

Asymptomatic infection is defined as infection in which serum antibody is present, but there is no known history of clinical outbreaks. However, up to two thirds of patients with identified asymptomatic HSV-2 infection actually have unrecognized symptomatic infection. Patients should be informed about clinical signs and symptoms of genital herpes, as this may help them recognize symptomatic infection.

The rates of asymptomatic shedding are greater with HSV-2 than HSV-1. Studies show that asymptomatic shedding occurs in almost all persons seropositive for HSV-2. Most HSV-2 is transmitted during asymptomatic shedding.

The most common sites of asymptomatic shedding are the vulva and perianal areas in women and penile skin and perianal area in men. Shedding rates are greatest in the first three months after infection. Asymptomatic shedding is of briefer duration than shedding during clinical recurrences.

The presence of HSV-1 serum antibody seems to decrease rates of asymptomatic shedding with HSV-2. Chemosuppression reduces but does not eradicate shedding.

Sources: CDC, DHHS