Headache is a very common disorder in children and adolescents. While migraine and tension headaches are well-known and diagnosed by pediatricians, a group of primary headaches in children, rare in frequency, are poorly understood and likely underestimated by physicians, resulting in delayed diagnosis and treatment. This review aims to provide an updated overview of these clinical forms, considering new evidence. We will present the main clinical, therapeutic, and pathophysiological aspects and possible future hypotheses, with specific reference to pediatric cases of the following clinical forms: cough headache, thunderclap headache, cold headache, primary stabbing headache, nummular headache, hypnic headache, red ear syndrome, and non-odontogenic orofacial pain. These clinical forms currently pose a major diagnostic challenge for pediatricians and represent a source of serious disability for children and adolescents.

Sleep and headache are strongly interconnected, this narrative review gives an overview of the current pathophysiological and clinical correlates of sleep in primary headache disorders. Circuits across the brainstem and hypothalamus that are involved in the regulation of sleep and wake overlap with known headache and pain pathways, offering a possible pathophysiological basis for this relationship. Furthermore, growing evidence supports a key role for orexin (hypocretin), with dysregulated signalling and widespread orexin receptor expression in the trigeminocervical complex and trigeminal ganglion, key structures in headache pathophysiology. Clinically, people with migraine frequently report poor subjective sleep quality, high rates of insomnia, and an increased prevalence of sleep disorders such as restless legs syndrome. Additionally, reduced sleep is often reported as a trigger for migraine attacks. Cluster headache (CH) shows a particularly close relationship with sleep with attacks that occur at night during sleep. Polysomnography studies did not provide evidence for an association between specific sleep stages and attacks. Nonetheless, attacks often lead to impaired sleep quality and excessive daytime sleepiness in people with CH. Hypnic headache (HH) is characterized by headache attacks that occur exclusively during sleep. Lastly, sleep disturbances are also common in people with tension-type headache (TTH), particularly insomnia and daytime sleepiness. However, objective sleep studies generally show normal sleep architecture. Overall, substantial (patho)physiological and clinical overlap between headache and sleep disorders highlights the importance of systematically assessing and addressing of sleep disturbances in people with headache.

“Other primary headaches” is a group of heterogeneous headache disorders described in Chapter 4 of the third edition of the International Classification of Headache Disorders (ICHD-III). Due to the limited number of cases, most of these disorders are considered rare and represent a diagnostic and therapeutic challenge for clinicians and headache specialists. To increase knowledge, improve their recognition, and foster research on these rare headache disorders, this review provides a comprehensive up-to-date description of their hallmarks, including epidemiologic data, key clinical characteristics, proposed pathophysiological mechanisms, and suggested treatments. Diagnosing rare headache disorders is challenging. A few key clinical features can help improve their recognition and distinction. These include identifying a specific trigger or stimulus for headache development such as cough, exercise, or sexual activity, a particular pattern of onset or recurrence, like for hypnic headache, primary thunderclap headache, or new daily persistent headache, or a unique scalp location for the pain such as for nummular headache or epicrania fugax. These clinical details are crucial for narrowing the differential diagnosis and making the correct diagnosis. However, regardless of the specificity of the clinical presentation, secondary causes must be ruled out when facing patients with these rare clinical presentations. Limited evidence on the pathophysiology and treatment of these disorders is available, and high-quality studies are lacking. Accurate diagnosis and additional research on these rare headache disorders are needed. Multicenter and international collaborations within the framework of international headache societies and among tertiary headache centers are key to developing efficient and high-quality registries and databases. Additionally, clinical trials are needed to develop evidence supporting the treatments current in use and to address the unmet needs of these rare diseases. Only through these efforts it will be possible to design specific studies to increase our understanding of these rare disorders and improve the quality of life of individuals living with these conditions. Headache disorders are among the leading causes of morbidity and years lived with disability worldwide. Headaches have been classified into various categories based on the International Classification of Headache Disorders Criteria. Hypnic headache (HH) is a rare, primary headache disorder that occurs exclusively during sleep, usually simultaneously each night. Previously, HH was referred to as "the clockwise headache" or "alarm clock headache." The International Classification of Headache Disorders, 3rd ed classifies hypnic headache as a primary headache disorder. HH is characterized by attacks of dull headache that typically present after age 50, occur at least 10 times per month, and occur during sleep without associated autonomic symptoms. The attacks awaken the patient from sleep and usually last 15 minutes to 4 hours after waking. Hypnic headache is a chronic disorder that can last for many years, but has moderate remission rates with treatment. Patients with migraine and hypertension are more likely to develop HH. Nearly all patients with HH exhibit motor activity during the attack, such as getting out of bed, eating, drinking, showering, or reading when awakened by the headache. However, the restlessness is less severe than cluster headache and trigeminal autonomic cephalalgias. Other causes of nocturnal headache and secondary headaches should be excluded before confirming a diagnosis of HH.

Many headaches at night arise due to primary headache disorders, which occur independently of other symptoms and are not caused by another medical condition. Primary headache disorders with nighttime attacks can include tension-type headaches, migraines, hypnic headaches, and cluster headaches. A hypnic headache is sometimes called an "alarm clock headache" because symptoms tend to arise at the same time of night. Apart from considering primary headaches, secondary causes of nighttime headaches should be considered and ruled out, in particular headaches secondary to intracranial hypertension, temporomandibular joint issues (like bruxism) and sleep apnea. Treatments vary based on headache type but often include a combination of medications and prevention strategies. This review article covers the basics of nighttime primary headaches in children, including pathophysiology, etiology, clinical features of the different forms and their treatment. It will also discuss the differences in headache features between children and adults.

Paroxysmal hemicrania (PH) and hypnic headache (HH) are rare indomethacin-responsive headache syndromes. This case report details the new onset of both disorders in a woman in her late 60s. One headache type presented as severe pain centered on the right eyebrow, lasting 30 minutes, occurring more than 8 times daily, and associated with ipsilateral lacrimation and rhinorrhea. The second type was a right frontal severe pain, with onset at 4 a.m., occurring only during sleep, lasting 30 minutes, and with no associated factors. The patient's response to indomethacin for both headache types was confirmed through an unblinded ABAB study design: complete resolution of headaches during indomethacin use and recurrence upon discontinuation. This case highlights the rarity of co-morbid indomethacin-responsive headaches and underscores the diagnostic and therapeutic challenges associated with these conditions.