This clinical practice guideline addresses the diagnosis and treatment of primary adrenal insufficiency (PAI). It recommends diagnostic testing for PAI in acutely ill patients with symptoms suggestive of the condition, including volume depletion, hypotension, hyponatremia, hyperkalemia, fever, abdominal pain, hyperpigmentation, and hypoglycemia in children. A corticotropin stimulation test is recommended for confirmation when appropriate. Immediate hydrocortisone therapy is advised in severe cases or adrenal crisis before diagnostic results are available. For diagnosis, a standard dose of 250 µg corticotropin stimulation test is recommended as the "gold standard." If not feasible, a morning cortisol level <140 nmol/L combined with ACTH levels may be used. Plasma ACTH and renin/aldosterone levels are also recommended for diagnosis. Autoantibodies against 21-hydroxylase should be measured to determine the cause of PAI. Treatment involves glucocorticoid replacement with hydrocortisone (15–25 mg/d) or cortisone acetate (20–35 mg/d) in two to three divided doses daily. Fludrocortisone is recommended for mineralocorticoid replacement. DHEA replacement may be considered in women with low libido and energy levels. Pregnant women with PAI should be monitored closely, with increased hydrocortisone doses during the third trimester. In children, hydrocortisone is recommended at 8 mg/m²/day. Patients should be educated on stress dosing and equipped with a steroid card and emergency glucocorticoid preparation. Follow-up should monitor corticosteroid dosing and associated autoimmune diseases. Adrenal crisis management includes immediate parenteral hydrocortisone treatment, followed by fluid resuscitation and continued hydrocortisone infusion. Prevention involves adjusting glucocorticoid doses based on illness severity or stressor magnitude. Patients should be educated on glucocorticoid adjustments during stressful events and adrenal crisis prevention strategies. Regular follow-up with an endocrinologist is recommended, with annual evaluations for over- and under-replacement. Periodic screening for autoimmune diseases is advised, especially in those with a history of autoimmune conditions. Genetic counseling is recommended for patients with PAI due to monogenic disorders. The guideline emphasizes the importance of early diagnosis and management to prevent life-threatening complications.This clinical practice guideline addresses the diagnosis and treatment of primary adrenal insufficiency (PAI). It recommends diagnostic testing for PAI in acutely ill patients with symptoms suggestive of the condition, including volume depletion, hypotension, hyponatremia, hyperkalemia, fever, abdominal pain, hyperpigmentation, and hypoglycemia in children. A corticotropin stimulation test is recommended for confirmation when appropriate. Immediate hydrocortisone therapy is advised in severe cases or adrenal crisis before diagnostic results are available. For diagnosis, a standard dose of 250 µg corticotropin stimulation test is recommended as the "gold standard." If not feasible, a morning cortisol level <140 nmol/L combined with ACTH levels may be used. Plasma ACTH and renin/aldosterone levels are also recommended for diagnosis. Autoantibodies against 21-hydroxylase should be measured to determine the cause of PAI. Treatment involves glucocorticoid replacement with hydrocortisone (15–25 mg/d) or cortisone acetate (20–35 mg/d) in two to three divided doses daily. Fludrocortisone is recommended for mineralocorticoid replacement. DHEA replacement may be considered in women with low libido and energy levels. Pregnant women with PAI should be monitored closely, with increased hydrocortisone doses during the third trimester. In children, hydrocortisone is recommended at 8 mg/m²/day. Patients should be educated on stress dosing and equipped with a steroid card and emergency glucocorticoid preparation. Follow-up should monitor corticosteroid dosing and associated autoimmune diseases. Adrenal crisis management includes immediate parenteral hydrocortisone treatment, followed by fluid resuscitation and continued hydrocortisone infusion. Prevention involves adjusting glucocorticoid doses based on illness severity or stressor magnitude. Patients should be educated on glucocorticoid adjustments during stressful events and adrenal crisis prevention strategies. Regular follow-up with an endocrinologist is recommended, with annual evaluations for over- and under-replacement. Periodic screening for autoimmune diseases is advised, especially in those with a history of autoimmune conditions. Genetic counseling is recommended for patients with PAI due to monogenic disorders. The guideline emphasizes the importance of early diagnosis and management to prevent life-threatening complications.