The varicella-zoster virus (VZV), which causes chickenpox, can reactivate years later as shingles. While the rash is most commonly associated with the torso, the virus can travel along any nerve pathway in the body, affecting the face and inside the mouth. This reactivation occurs when the dormant VZV, housed in the nerve ganglia, travels down the nerve fiber to the skin or mucosal surface.
How Shingles Affects the Facial and Oral Nerves
The mechanism for shingles appearing in the mouth is directly related to the virus’s pathway along specific cranial nerves. Once VZV reactivates, it travels along the axon toward the area of skin or mucosa that the nerve supplies. For the mouth and face, the trigeminal nerve (Cranial Nerve V) is the route the virus takes, as this nerve provides sensation to the majority of the face, teeth, and oral cavity.
The trigeminal nerve divides into three main branches: the ophthalmic (V1), maxillary (V2), and mandibular (V3) divisions. Involvement of the maxillary and mandibular branches leads to symptoms inside the mouth and on the jawline. If the virus travels along the maxillary nerve, lesions can appear on the upper gums and the hard palate (the roof of the mouth). Reactivation along the mandibular nerve can cause the outbreak to manifest on the lower gums, the tongue, and the skin of the lower face.
Since the virus strictly follows the nerve path, the resulting lesions are almost always unilateral, affecting only one side of the face or mouth. This one-sided presentation helps medical professionals differentiate oral shingles from other blistering conditions. The virus causes inflammation and damage to the nerve fiber itself, which explains the intense pain that often precedes the physical eruption.
Recognizing Symptoms of Oral and Facial Shingles
The onset of oral and facial shingles begins with a prodromal phase lasting one to three days, before any visible rash appears. During this time, a deep, intense burning, tingling, or shooting pain is felt along the affected nerve path, sometimes mimicking a severe toothache or facial tenderness. This early pain can sometimes lead to misdiagnosis or unnecessary dental procedures.
The acute eruptive phase follows, marked by a cluster of small, fluid-filled blisters (vesicles) on the face or within the mouth. Inside the mouth, these blisters develop on the tongue, gums, hard palate, or inner cheek. Unlike skin lesions that crust over and dry, oral blisters break open quickly due to the moist environment, forming painful, shallow ulcers that heal over one to two weeks.
Facial swelling, redness, and sensitivity in the affected area are common symptoms. When the ophthalmic branch (V1) is involved, the rash affects the forehead and eyelid, and the eye may be directly affected. Any sign of lesions near the eye, or eye pain, warrants immediate consultation with an ophthalmologist, as it carries a risk of vision loss. Difficulty chewing, speaking, and swallowing are frequent complaints due to the sensitivity and pain of the ulcers.
Medical Management and Long-Term Prevention
Timely diagnosis and treatment are important for managing an acute shingles outbreak and minimizing complications. Treatment relies on antiviral medications such as acyclovir, valacyclovir, or famciclovir, which inhibit the virus’s ability to replicate. These medications are most effective when started within the first 72 hours of the rash appearing, as early intervention reduces the severity and duration of the illness.
Pain management for oral lesions involves over-the-counter pain relievers, though severe nerve pain may require stronger prescription medications, including anticonvulsants or topical lidocaine patches. The most significant long-term complication is postherpetic neuralgia (PHN), where nerve pain persists for months or years after the rash has healed. PHN is caused by damage to the nerve fibers during the acute infection, characterized by chronic burning, stabbing, or shock-like pain.
Prevention is the most effective strategy against both shingles and PHN, achieved through vaccination. The recombinant zoster vaccine is highly effective at preventing shingles and is recommended for adults 50 years and older. Even if a person has already had shingles, vaccination is recommended to reduce the risk of future recurrence and lessen the severity of a potential outbreak.