Headache and Herpes Zoster

Medical Student Pearl

James Tang

Dalhousie University Class of 2023

Reviewed by: Dr. Erin Slaunwhite

Copyedited by: Dr. Janeske Vonkeman

Case

Mr. H is a 57 yo gentleman who presents to the ED complaining of a 3-day history of headache. He describes a progressive worsening of a constant dull ache unilaterally above his left eye. It’s currently a 4-5/10 in severity and does not radiate. He has not had any nausea or vomiting, and no phonophobia but asks you to dim the lights in the room if that’s possible. He has no previous history of the same. He has not noticed any shooting pains associated with eating or drinking cold foods/liquids. He denies any associated autonomic symptoms on that side. Mr. H tells you he’s tried Tylenol and Advil at home and although it seemed to help a bit initially, the pain has continued to worsen over the last couple of days. He hasn’t noted any changes in the severity of his headache with physical activity.

Mr. H has no relevant past medical history and does not take any regular medications. He enjoys drinking 1-2 beers on the weekends, does not use cannabis, and has never used any other recreational drugs.

On physical exam, Mr. H appears his stated age and appears quite tanned from his job in construction. His vital signs are within normal limits. On close inspection, you make note of an area of erythematous macules and papules forming on his left forehead and extending 1-2 cm above and below his scalp line. The area is mildly tender to touch. His cranial nerve exam was otherwise normal. His remaining neuro exam, as well as head and neck, cardiac, respiratory, and abdominal exams were all normal.

A general approach to primary headache – Tension TIC TAC TOE

The International Headache Society (IHS) outlines specific diagnostic criteria for headache disorders within their International Classification of Headache Disorders (ICHD 3^rd edition).¹ Below is an abbreviated summary of the select common diagnoses that the ICHD discusses in much greater detail^2-5:

Danger signs – features suggestive of secondary headache (e.g. space-occupying lesion, sub-arachnoid hemorrhage, cervical artery dissection, giant cell arteritis, infection, trauma, etc)^2,4,5:

• Systemic symptoms including fever, weight loss, progressive N/V
• Neoplasm history
• Neurologic deficit (including confusion, weakness, vision loss, numbness, impaired alertness, side locked headache)
• Onset is sudden or abrupt (thunderclap)
• Older age (> 50 yo)
• Pattern change from previous headaches
• Positional headache
• Precipitated by Valsalva or exertion
• Papilledema
• Progressive headache and atypical presentations
• Pregnancy or puerperium
• Post-traumatic onset of headache
• Pathology of the immune system such as HIV

Patients with danger signs suggestive of secondary headache should be considered for imaging. If a primary headache is suspected but imaging is performed for no other reason than reassurance, it can be detrimental to the patient if the results return incidental findings (e.g. vascular lesion) likely unrelated to the headache.

But our patient’s presentation doesn’t really seem to fit into any of these categories…

Herpes Zoster

In immunocompetent individuals, the diagnosis of herpes zoster is based solely on the clinical presentation: unilateral, usually painful vesicular eruption with a well-defined dermatomal distribution (see Figure 1). Prodromal symptoms include malaise, headache, photophobia, abnormal skin sensations, and occasionally fever. These symptoms may occur one to five days before the appearance of the rash. Age is the most important risk factor for the development of herpes zoster. A dramatic increase in the age-specific incidence of herpes zoster begins at approximately 50 years of age with 40% occur in people at least 60 years of age.⁶ It is estimated that approximately 50% of persons who live to 85 years of age will have had an episode of herpes zoster.⁶

Figure 1. Vesicular eruption in keeping with herpes zoster ophthalmicus with a crusted skin rash following the V1 dermatomal distribution and does not cross midline.⁷

Antiviral therapy is the first-line treatment and should be initiated within 72 hours of rash onset to increase the rate of healing, decrease the duration of acute herpes zoster, and decrease severity and pain. Ideally, initiation of antiviral therapy should be started during the pre-eruptive phase of herpes zoster, but often the diagnosis can only be confidently made once the distinctive rash presents.

See Table below for antiviral doses⁹:

Pain management

For acute herpes zoster, mild to moderate pain may be controlled with acetaminophen and/or nonsteroidal anti-inflammatory drugs. For those with moderate pain not responding to acetaminophen and nonsteroidal anti-inflammatory drugs, a short course of a short acting opioid such as hydromorphone or morphine could be considered or a course of corticosteroids. If the pain does not rapidly respond to opioid analgesics or if opioids are not tolerated, the addition of an adjunctive therapy should be considered including nortriptyline, gabapentin, or pregabalin. Despite these adjunctive therapies not having been extensively studied in patients with acute herpes zoster pain, they have evidence for other forms of nerve-type pain.⁸ The addition of corticosteroids to acyclovir decreases the pain of acute herpes zoster and speeds lesion healing and return to daily activities. Combination therapy with corticosteroids and antivirals should be considered in older patients with no contraindications.⁸

Theoretical models suggest that reducing pain during the acute phase of herpes zoster may stop the initiation of the mechanisms that cause chronic pain, thus reducing the risk of postherpetic neuralgia.⁸

Postherpetic neuralgia

Postherpetic neuralgia is the most common complication of herpes zoster.⁹ It occurs in ~30% of patients older than 80 years and ~20% of patients 60 to 65 years; it is rare in patients younger than 50 years.⁶ Postherpetic neuralgia may persist from 30 days to more than 6 months after the lesions have healed, and most cases resolve spontaneously.⁹ Although antiviral medications slow the production of the virus and decrease the viral load in the dorsal root ganglia, evidence showing that these medications alter the incidence and course of postherpetic neuralgia is inconsistent.⁸ The major risk factors for postherpetic neuralgia are older age, greater acute pain, and greater rash severity.⁸

Case conclusion

Mr. H’s headache did not fit into any specific category of headache as is often the case. Although he did meet the criteria for certain danger signs (e.g. age >50), imaging was forgone due to the finding of an erythematous maculopapular rash over his forehead. Mr. H’s rash followed the dermatomal distribution of the ophthalmic branch of the trigeminal nerve and was highly suspicious of an early herpes zoster outbreak.

The patient was given a prescription for valacyclovir to take for 7 days with instructions to seek care if lesions break out close to his eye or his pain becomes unmanageable with over-the-counter analgesia. Herpes zoster opthalmicus can be a sight-threatening condition that requires close ophthalmology follow up if there is any concern of lesions near or in the eye or the patient has clinical signs or symptoms. Mr H inquired about getting the shingles vaccine and was advised to follow up with his family doctor to arrange this following resolution of his rash.

Key Takeaways

• Have a structured approach to understanding the different classes of primary headaches
• Know the danger signs that could be suggestive of a secondary headache
• Clinical judgement should be prioritized in determining who to image
• Herpes zoster is a clinical diagnosis in immunocompetent individuals
• Appropriate pain management of acute herpes zoster and vaccination can help prevent chronic pain syndromes

References

1. The International Classification of Headache Disorders – ICHD-3. Accessed June 24, 2022. https://ichd-3.org/
2. Evaluation of Acute Headaches in Adults. Accessed June 24, 2022. https://www.aafp.org/pubs/afp/issues/2001/0215/p685.html
3. Primary care management of headache in adults Clinical Practice Guideline | September 2016 2 nd Edition. Published online 2016.
4. Ponka D, Kirlew M. Top 10 differential diagnoses in family medicine: Headache. Can Fam Physician. 2007;53(10):1733. Accessed June 24, 2022. /pmc/articles/PMC2231438/
5. Do TP, Remmers A, Schytz HW, et al. Red and orange flags for secondary headaches in clinical practice: SNNOOP10 list. Neurology. 2019;92(3):134-144. doi:10.1212/WNL.0000000000006697
6. Epidemiology, clinical manifestations, and diagnosis of herpes zoster – UpToDate. Accessed June 24, 2022. https://www.uptodate.com/contents/epidemiology-clinical-manifestations-and-diagnosis-of-herpes-zoster
7. Darren Shu JT, Ghosh N, Ghosh S. Herpes zoster ophthalmicus. BMJ : British Medical Journal (Online). 2019;364. doi: https://doi.org/10.1136/bmj.k5234.
8. Herpes Zoster and Postherpetic Neuralgia: Prevention and Management. Accessed June 24, 2022. https://www.aafp.org/pubs/afp/issues/2011/0615/p1432.html
9. Clinical Overview of Herpes Zoster (Shingles) | CDC. Accessed June 24, 2022. https://www.cdc.gov/shingles/hcp/clinical-overview.html