23 patients and 6 healthy controls were requested to participate in this study. Examination of skin samples consisted of light microscopic estimation as well as, transmission electron microscopic techniques (TEM) and immunohistochemical techniques. The total number of mast cells (MCs) was significantly higher in cluster headache (CH) patients than in controls, but differences between painful region and opposite temporal site were inconclusive. TEM search revealed presence of MCs around nerve fibres. There were no plasma cells containing polyclonal Ig, IgA, IgG and IgM according to horseradish peroxidase techniques. These observations suggest the role of MCs in CH pathogenesis, which support author's previous findings and results of others as well. The lack of PCs may indicate no involvement of B-cell mediated phenomena but of T-cell one, of which MCs are special part.