Headache is a common accompaniment of systemic viral infections such as influenza, encephalitis, meningitis, HIV, and COVID. It is also common with sepsis. More rarely it may accompany other systemic infections. In intracranial infections, headache is usually the first and the most frequently encountered symptom. Occurrence of a new type of headache that is diffuse and associated with focal neurological signs and/or altered mental state and a general feeling of illness and/or fever should direct attention towards an intracranial infection even in the absence of neck stiffness.
The common cold and influenza (flu) are the most common syndromes of infection in human beings. These diseases are diagnosed on symptomatology, and treatments are mainly symptomatic. Headache is a common symptom of influenza, probably caused by cytokines released from immune cells in response to viral infection. (Eccles, 2005) The clinical phenotype of headache attributed to influenza infection was similar to other infections, with more pronounced cranial autonomic symptoms. The most common phenotype was a bilateral headache, with frontal topography and moderate intensity. (Garcia-Azorin et al, 2023)
Meningitis is an inflammatory syndrome involving the meninges that classically manifests with headache and nuchal rigidity and is diagnosed by cerebrospinal fluid examination. In contrast, encephalitis refers to inflammation of the brain parenchyma itself and often results in focal neurologic deficits or seizures. A review of systems is helpful, including weight loss, night sweats, fever, rash, cough, nausea, vomiting, diarrhea, and rheumatologic symptoms such as joint pain, xerostomia, or xerophthalmia. (Richie & Josephson, 2015)
Bacterial meningitis and viral encephalitis, particularly herpes simplex encephalitis, are severe neurological infections that, if not treated promptly and effectively, lead to poor neurological outcome or death. (Gaieski et al, 2015)
HIV-positive patients had a high frequency of headaches, which had a great impact on patients' lives. The pattern most often found was migraine. A recent cross-sectional study found that the lower the CD4 count was, the greater the severity and impact of the headache also were. (Sampaio et al, 2017)
Headache is a clinically significant symptom of COVID-19. Possible mechanisms for the occurrence of headache in COVID-19 include direct viral injury, the inflammatory process, hypoxemia, coagulopathy, and endothelial involvement. (Sampaio, 2022)
The various neurological disorders associated with COVID-19 range in severity from mild symptoms such as headache, or myalgias to more severe symptoms such as stroke, psychosis, and anosmia. (Ahmad et al, 2022)
Eccles R. Understanding the symptoms of the common cold and influenza. Lancet Infect Dis. 2005 Nov;5(11):718-25. doi: 10.1016/S1473-3099(05)70270-X. PMID: 16253889; PMCID: PMC7185637.
García-Azorín D, Santana-López L, Lozano-Alonso JE, Ordax-Díez A, González-Osorio Y, Rojo-Rello S, Eiros JM, Sánchez-Martínez J, Recio-García A, Sierra-Mencía Á, Sanz-Muñoz I, Guerrero-Peral ÁL. InfluenCEF study: Clinical phenotype and duration of headache attributed to influenza infection. Cephalalgia. 2023 Nov;43(11):3331024231212900. doi: 10.1177/03331024231212900. PMID: 37950674.
Richie MB, Josephson SA. A Practical Approach to Meningitis and Encephalitis. Semin Neurol. 2015 Dec;35(6):611-20. doi: 10.1055/s-0035-1564686. Epub 2015 Nov 23. PMID: 26595861.
Gaieski DF, Nathan BR, O'Brien NF. Emergency Neurologic Life Support: Meningitis and Encephalitis. Neurocrit Care. 2015 Dec;23 Suppl 2:S110-8. doi: 10.1007/s12028-015-0165-2. PMID: 26438456.
Sampaio Rocha-Filho PA, Torres RCS, Ramos Montarroyos U. HIV and Headache: A Cross-Sectional Study. Headache. 2017 Nov;57(10):1545-1550. doi: 10.1111/head.13183. Epub 2017 Sep 14. PMID: 28905376.
Sampaio Rocha-Filho PA. Headache associated with COVID-19: Epidemiology, characteristics, pathophysiology, and management. Headache. 2022 Jun;62(6):650-656. doi: 10.1111/head.14319. Epub 2022 May 11. PMID: 35545780; PMCID: PMC9348060.
Ahmad SJ, Feigen CM, Vazquez JP, Kobets AJ, Altschul DJ. Neurological Sequelae of COVID-19. J Integr Neurosci. 2022 Apr 6;21(3):77. doi: 10.31083/j.jin2103077. PMID: 35633158.