Mast Cell Activation Disease (MCAD) is characterized byabnormal proliferation of mastocytes, where clinical manifestationsarise from the excess release of these cells’ mediators.This case report concerns a 34-year old male patientwho seeks medical attention after 5 months presenting recurringepisodes of intense facial flushing with local edema,erythema, and increased volume of the ears and lips, withoutsigns of angioedema. Other symptoms included burningoropharyngeal pain, vascular-type headache and hypotension.These crises occurred predominantly during nighttimeand lasted 20-60 minutes, and were often associated withprolonged exposure to sunlight, high temperatures and psychologicalstress; constituting a clinical picture compatiblewith MCAD, supported by laboratory findings. Treatment beganwith ebastine, deflazacort, montelukast, ranitidine andomega-3 fatty acids, without clinical improvement, leading tosubstitution of this regimen with sodium chromoglycate andinitiation of an immunomodulatory diet. This plan achievedsatisfactory symptomatic resolution, confirming the diagnosisand highlighting the importance of adequate pharmacologicintervention. During a control consultation, the patientreported nocturnal episodes of tachycardia, palpitations andanxiety unrelated to the flushing crises, which prompted thyroidevaluation, revealing autoimmune thyroid disease withsubclinical hyperthyroidism, which was managed with methimazolwithout complications