Abstract
Dear Sir Nummular headache (NH) may be considered as primary neuralgia characterized by focal pain in a single round or elliptical area of the head surface (1). The pain is unilateral, usually chronic and mild to moderate in intensity, with exacerbations that are often superimposed on a baseline pain (2). We report a case of NH with complete responsiveness to indomethacin.
A 40-year-old man came to our observation with a six month history of focal head pain in the right parietal region. His past medical history was unremarkable. The headache began without any precipitant. The affected area was perfectly circular, with a 3 cm diameter. The pain was continuous, dull and pressing, graded 2–3 out of 10 in intensity on a 10-point verbal numeric scale (VNS), with one or two daily exacerbations lasting hours and characterized by a stabbing ache graded 5–7 by VNS. The affected area was occasionally tender to the touch.
Neurological examination was completely negative, as well as routine blood tests, including erythrocyte sedimentation rate and screening for immunological disorders. The patient underwent both computed tomography and MRI scans of the brain, which proved normal. The patient tried paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and ketoprophene, with no or partial relief. Amitriptyline 30 mg/day for one month, gabapentin 900 mg/day for one month and dexamethasone 8 mg/day intramuscular (IM) for 10 days were used without benefit. An Indotest (3) (indomethacin 50 mg IM) was performed, with complete pain relief after just approximately 45 minutes. Hence, trial with indomethacin per os (25 mg BID) provided complete pain relief. After two weeks' treatment, the indomethacin trial was stopped, but the pain recurred with the same characteristics within few days. Thus, the trial was restarted, again with a prompt response. After one month, the medication was definitely discontinued and the patient remained pain-free during two months follow-up.
Only a few cases of NH have been reported to date, and not much is known about NH treatment. The sharply delimited borders of the painful area suggest a peripheral cause; possible mechanisms proposed are a neuropathy of a terminal branch of a cutaneous scalp nerve and a focal, nociceptive-type pain stemming from epicranial tissues (2).
According to the hypothesis of a neuropathic origin of the pain in NH, the drugs which usually work in neuropathic pain have been the most broadly used as prophylaxis; however, especially in cases of moderate-to-severe pain, response to treatment is often unsatisfactory, as previously reported by Ruscheweyh et al. (4).
Our case report fulfills the proposed diagnostic criteria for NH (1), and a complete response to indomethacin was observed. Indomethacin responsiveness in NH has been appropriately investigated in only few cases, with contradictory results (4–7). NH is one of the strictly unilateral headaches, and its responsiveness to indomethacin may raise the question of whether NH could share not only clinical but also pathogenetic features with other strictly unilateral headaches which are indomethacin responsive. The indomethacin-responsive headaches seem to have a central origin of pain; to the contrary, in NH the source is supposed to be peripheral, although a possible central contribution cannot be excluded. As discussed above, NH may be resistant to the medical therapy commonly used in neuropathic pain, and recently a relationship between NH and menstrual hormone variations has been reported (8).
The clinical points here are (1) indomethacin could be a valid alternative approach in clinical practice; in fact, some patients have been reported to partially respond to this treatment and we report a case with dramatic response; and (2) Indotest, in our patient, turned out to be a useful and easy-to-use tool to detect an early-indomethacin-responder patient.