Muscular pain and fatigue
Muscular pain and fatigue are the most frequent symptoms identified in the consultations. Once possible lesions, traumatisms, overcharges, adverse effects of drugs, or other diseases have been discarded, it may be thought that histamine accumulation could cause muscular pain and fatigue.
Currently, more studies on this relationship are needed, but based on the clinical evidence it can be confirmed that patients diagnosed with chronic fatigue, fibromyalgia or general muscular pain, experience symptom improvement after been diagnosed with DAO deficiency and treated with a strict low-histamine diet.
Histamine is a molecule with multiple functions, one of these is the contraction and relaxation of the smooth muscle of the blood vessel and bronchi. It also acts as a neurotransmitter in the central nervous system, and participates in the control of the sleep-wake cycle. Taking the above into account, it is reasonable to believe that this amine can provoke an imbalance in their functions triggering pain and fatigue. For this reason, when lowering histamine intake through diet, symptoms improve.
In 2014, a study related Multiple Sclerosis (MS) to histamine excess and DAO deficiency. MS is a chronic disease of the nervous central system and can show symptoms such as fatigue, pain, lack of balance, etc. In this case, histamine could play a significant role, as it is able to increase blood-brain barrier permeability (BBB), thus facilitating the flow of cells of the immune system and causing a pro-inflammatory effect.