A 59-year-old man was referred to the authors’ medical clinic with a history of four episodes of collapse over five years. The patient had a history of urticaria pigmentosa diagnosed 12 months previously. The recognition of his skin condition and the history of recurrent, albeit infrequent, collapses accompanied by hypotension and pruritis led to the suspicion of mastocytosis. He had persistent elevation of serum tryptase consistent with mast cell disease, but the analysis of a bone marrow biopsy failed to confirm systemic disease. Mastocytosis can lead to numerous symptoms directly related to the degranulation of mast cells by certain physical and pharmacological stimuli, and can present with recurrent anaphylactic attacks. Provision of an EpiPen can be life-saving in affected individuals. The association of urticaria pigmentosa and mastocytosis is of vital importance to physicians who are frequently faced by patients presenting with collapse without cause.