Areas of trigeminal nerve innervation, especially the ophthalmic branch, are most commonly affected by herpes zoster, as well as the skin of the T3-L2 segments of the trunk. Skin lesions on the chest are observed in more than 50% of cases, and rashes are least likely to occur on the skin of the distal extremities. The lesions may be located in the sacral region, leading to the development of a neurogenic bladder picture with urinary dysfunction and retention (due to virus migration to adjacent autonomic nerves); it may be associated with herpes zoster of the sacral dermatomes S2, S3, or S4.

Common symptoms

The clinical picture of herpes zoster includes both cutaneous manifestations and neurological disorders. Approximately 20% of patients experience general symptoms such as fever, headache, malaise, increased fatigue, regional lymph node enlargement, and cerebrospinal fluid changes (lymphocytosis and monocytosis). Pain often precedes skin changes and, with appropriate localization, may mimic myocardial infarction, appendicitis, renal colic, etc. The most common site of pain is along the intercostal nerves.

Abortive herpes zoster (incognito)

Characterized by the appearance of erythematous plaques and papules, but vesicles do not develop.

Bullous herpes zoster

Occurs when vesicles merge. It is characterized by blisters, erosions, and scabs.

Hemorrhagic herpes zoster

In hemorrhagic form of the disease, vesicles contain blood, the process extends deep into the dermis, and scabs become dark brown.

Gangrenous herpes zoster

In some cases, the base of the vesicles becomes necrotic and a gangrenous form develops, characterized by the formation of grouped small black scabs. After healing, scars of appropriate size remain. The usual course of herpes zoster is 2-4 weeks, while the gangrenous form can last 2-3 months.

Generalized Herpes Zoster

In some patients (2-4%), a generalized form of herpes zoster is observed: in addition to the usual site of infection, a more or less widespread rash consisting of vesicles, resembling elements of chickenpox, appears throughout the entire skin along with eruptions along the nerve trunk. Recurrent episodes of infection in the form of generalized rashes are usually not observed.

In the presence of immunodeficiency (including HIV infection), skin manifestations can appear far from the affected dermatome, known as the disseminated form. The likelihood and degree of dissemination of lesions on the skin increase with the patient's age. Disseminated forms include:

• Herpes zoster with acute disseminated skin lesions: Multiple vesicles and blisters on different areas of the skin and mucous membranes. After the vesicles and blisters rupture, erosions form, which then dry and form scabs. The number of elements varies from two or three to several hundred. The clinical picture resembles a combination of chickenpox and herpes zoster.
• Herpes zoster with chronic disseminated skin lesions: Vesicles and blisters (including on the palms and soles) appear continuously. They may be generalized or limited to one or more dermatomes. Vesicles and blisters leave behind nodules, ulcers and ecthyma-like elements (deep ulcers covered with scabs). Healing is prolonged and post-inflammatory hypo- or hyperpigmentation may occur.

Oral Herpes Zoster

Involvement of the second and third branches of the trigeminal nerve and other cranial nerves may lead to eruptions on the mucous membranes of the oral cavity (tongue, hard palate, gums), pharynx, and larynx.

Hyperkeratotic herpes zoster

A rare form of the disease characterized by the continuous accumulation of keratinous masses or focal hyperkeratotic plaques, papules, or nodules, sometimes resembling cutaneous horns and warts. The eruptions persist in one or more adjacent dermatomes over a prolonged period. It is almost always seen in HIV-infected patients, but is rarely seen in HIV-negative individuals. It is also known as verrucous herpes zoster.

Herpes zoster ophthalmicus

Herpes zoster ophthalmicus is the herpetic involvement of any branch of the ophthalmic nerve. In 10-15% of patients, the ophthalmic branch of the trigeminal nerve may be involved, with eruptions on the skin extending from the level of the eye to the temporal region, with a sharp termination along the midline of the forehead. Involvement of the nasociliary branch, which innervates the eye, tip and lateral parts of the nose, allows the virus to invade the ocular structures. The cornea is often involved, leading to the development of keratitis. In addition, other parts of the eyeball may be affected, resulting in episcleritis, iridocyclitis, and inflammation of the iris.

The retina is rarely involved in the pathological process (as hemorrhages or emboli), but the optic nerve is more often affected, leading to optic neuritis with subsequent atrophy (possibly due to the extension of meningeal processes to the optic nerve). In herpes zoster with ocular involvement, the eruptions spread from eye level to the top of the head, but do not cross the midline.

Hunt syndrome

Hunt syndrome is a ganglionitis of the geniculate ganglion of the facial nerve caused by the varicella-zoster virus. It manifests as pain in the ganglion, often radiating to the face, occiput, neck, eruptions in the external auditory canal, tympanic membrane, sometimes on the tongue and palate, paralysis of the facial muscles, and vestibulocochlear nerve involvement with dizziness, tinnitus, and hearing loss on the affected side.

Characteristics of Hunt syndrome include pain in the external auditory canal, eruptions in the external auditory canal, facial muscle paralysis, and decreased taste sensation in the anterior two-thirds of the tongue.

Herpes Zoster in Children

Intrauterine infection is possible in newborns whose mothers had a primary infection with varicella-zoster virus (VZV) during pregnancy. These children develop herpes zoster without prior chickenpox. Infantile herpes zoster often results in temporary paralysis of the affected limb.

There have been rare reports of herpes zoster in young children. Risk factors for occurrence in children include maternal chickenpox during pregnancy or primary VZV infection in the first year of life. The risk of developing the disease is higher in children who have had chickenpox before the age of 1 year. Herpes zoster in children is generally less severe than in older patients, with milder pain symptoms, and postherpetic neuralgia is less common.

Herpes zoster in HIV-infected patients

The risk of developing herpes zoster is higher in HIV-infected patients, and recurrences of the disease are more common. Additional symptoms may occur due to motor nerve involvement (in 5-15% of cases). The course of herpes zoster is more prolonged in HIV-infected individuals, and gangrenous and disseminated forms occur more frequently (25-50%), with severe internal organ (lung, liver, brain) involvement noted in 10% of cases in this category. In HIV-infected individuals, recurrences of herpes zoster involving one or more adjacent dermatomes are common.

Herpes zoster in pregnant women

The disease in pregnant women may be complicated by the development of pneumonia or encephalitis. VZV infection in the first trimester of pregnancy leads to primary placental insufficiency and is usually associated with pregnancy loss. The presence of infection should be the basis for intensive prevention of hemodynamic consequences (placental insufficiency, intrauterine hypoxia, intrauterine fetal growth restriction).

Pain syndrome in herpes zoster:

Pain is the primary symptom of herpes zoster. It often precedes the development of the rash and may persist after the rash has resolved, leading to postherpetic neuralgia. Pain in herpes zoster and postherpetic neuralgia is caused by different mechanisms. In the early stages, anatomical and functional changes occur that lead to the development of neuralgia - this explains the relationship between the severity of the initial pain and the subsequent development of postherpetic neuralgia, as well as the reasons for the failure of antiviral therapy in its prevention.

Pain syndrome associated with herpes zoster has three phases: acute, subacute, and chronic (postherpetic neuralgia). The acute phase of pain occurs during the prodromal period and lasts up to 30 days. The subacute phase of pain follows the acute phase and lasts no longer than 120 days. Pain lasting longer than 120 days is defined as postherpetic neuralgia, which can persist for several months or years, causing physical suffering and significantly reducing the quality of life of patients.

The immediate causes of prodromal pain are subclinical reactivation and replication of VZV in nerve tissue. Damage to peripheral nerves and neurons in ganglia serves as a trigger for afferent pain signals. In some patients, the pain syndrome is accompanied by generalized systemic inflammatory manifestations such as fever, malaise, myalgia, and headache.

In the majority of immunocompetent patients (60-90%), severe acute pain is accompanied by the appearance of a skin rash. The significant release of excitatory amino acids and neuropeptides caused by the blockade of afferent impulses during the prodromal and acute stages of herpes zoster can lead to toxic damage and death of inhibitory interneurons in the posterior horns of the spinal cord. The severity of acute pain increases with age. Excessive nociceptor activity and the generation of ectopic impulses can lead to increased and prolonged central responses to normal stimuli, known as allodynia (pain and/or unpleasant sensations induced by stimuli that are not typically painful, such as clothing touching the skin).

Predisposing factors for the development of postherpetic neuralgia include age over 50 years, female gender, the presence of prodromal symptoms, extensive rash, rash localization within the area of innervation of the trigeminal nerve or brachial plexus, severe acute pain, and immunodeficiency.

Three types of pain can be distinguished in postherpetic neuralgia:

• Constant, deep, dull, pressing, or burning pain.
• Spontaneous, periodic, stabbing, shooting, similar to an electric shock.
• Allodynia.

Pain syndrome is typically accompanied by sleep disturbances, loss of appetite and weight, chronic fatigue, depression, leading to social maladaptation of patients.