Primary adrenal insufficiency, also known as Addison's disease, is a rare but potentially fatal condition resulting from the failure of the adrenal cortex to produce glucocorticoid and/or mineralocorticoid hormones. Unfortunately, the clinical manifestation of primary adrenal insufficiency is not specific and often progresses insidiously, resulting in late diagnosis, or in severe cases, life-threatening circulatory collapse. Adrenal insufficiency should be considered in patients with unexplained vascular collapse. We report the case of a woman who presented to the emergency ward with unexplainable shock that was later diagnosed as adrenal crisis due to Addison's disease. The presence of hyperpigmentation in patients with rapid progression of adrenal insufficiency suggests the diagnosis of Addison's disease presenting with adrenal crisis.