trigeminal autonomic cephalalgia hemicrania continua https://rarediseases.info.nih.gov/diseases/10795/hemicrania-continua https://www.malacards.org/card/hemicrania_continua Orphanet:443070 Hemicrania continua (HC) is a type of primary headache disorder, which means the headache is not caused by another medical condition. Symptoms of HC include constant mild to moderate pain on one side of the head (unilateral) with periods of more intense, severe, migraine -like pain (exacerbations). These severe pain periods can last from 20 minutes to days. The frequency of exacerbations also varies greatly. The headache stays on the same side of the head and usually without pain free periods. HC is more common in women and most often starts in adulthood, but may begin anywhere from 5 to 67 years of age. Diagnosis of hemicrania continua (HC) is made by ruling out other possible causes of the pain and by clinical symptoms. During the periods of severe pain, at least one of the following symptoms must be present on same side of the body as the headache: watering or red eyes (conjunctival injection), congested or runny nose, or drooping eyelid. In addition, the headache pain must respond to treatment with indomethacin. The cause of HC is unknown. Other treatments for those who cannot tolerate long term indomethacin therapy are being studied. GARD:0010795 MONDO:0018615 UMLS:C2349425 SCTID:443095000 ICD10CM:G44.51 MEDGEN:748511 ICD9:339.41 icd11.foundation:1093161847