3.4 Hemicrania continua

Description:
Persistent, strictly unilateral headache, associated with ipsilateral conjunctival injection, lacrimation, nasal congestion, rhinorrhoea, forehead and facial sweating, miosis, ptosis and/or eyelid oedema, and/or with restlessness or agitation. The headache is absolutely sensitive to indomethacin.

Diagnostic criteria:
A. Unilateral headache fulfilling criteria B-D
B. Present for >3 months, with exacerbations of moderate or greater intensity
C. Either or both of the following:

    1. at least one of the following symptoms or signs, ipsilateral to the headache:

      a) conjunctival injection and/or lacrimation
      b) nasal congestion and/or rhinorrhoea
      c) eyelid oedema
      d) forehead and facial sweating
      e) forehead and facial flushing
      f) sensation of fullness in the ear
      g) miosis and/or ptosis

    2. a sense of restlessness or agitation, or aggravation of the pain by movement

D. Responds absolutely to therapeutic doses of indomethacin1
E. Not better accounted for by another ICHD-3 diagnosis.

Note:
1. In an adult, oral indomethacin should be used initially in a dose of at least 150 mg daily and increased if necessary up to 225 mg daily. The dose by injection is 100-200 mg. Smaller maintenance doses are often employed.

Comments:
Migrainous symptoms such as photophobia and phonophobia are often seen in 3.4 Hemicrania continua.

3.4 Hemicrania continua has been included under 3. Trigeminal autonomic cephalalgias in ICHD-3 (beta) (previously it was under 4. Other primary headache disorders) on the basis that the pain is typically unilateral, as are the cranial autonomic symptoms when present. Brain imaging studies show important overlaps between all disorders included here, notably activation in the region of the posterior hypothalamic grey. In addition, the absolute response to indomethacin of 3.4 Hemicrania continua is shared with 3.2 Paroxysmal hemicrania.