SUNCT is a rare condition characterised by a short-lasting periorbital pain associated with autonomic symptoms and is usually unresponsive to pharmacological treatment. We report a case of SUNCT syndrome linked to a pituitary micro-adenoma, with only nocturnal attacks. The nocturnal levels of prolactin (PRL) were increased, while other hormonal, haematological, serological and biochemical investigations and levels of PRL did not reveal abnormal findings during the day-time. PRL serum secretion after thyrotropin-releasing hormone test was lower than nocturnal secretion, but not enough to induce severe attacks. We suggest that in our patient the rise of nocturnal levels of PRL could have a direct role in the worsening of this headache, perhaps secondarily to an altered regulation of the hypothalamic-hypophysial axis, however the actual influence of sleep and the interaction between all neurotransmitters and hormones needs to be clarified further.