Why is there an increase in eosinophils (white blood cells) in primary adrenal insufficiency (Addison's disease)?

From the Guidelines

Increased eosinophils in primary adrenal insufficiency occur primarily due to cortisol deficiency, which normally suppresses eosinophil production and promotes their apoptosis, and this eosinophilia typically resolves with appropriate hormone replacement therapy. In primary adrenal insufficiency (Addison's disease), the adrenal glands fail to produce sufficient cortisol, a glucocorticoid hormone that plays a crucial role in regulating eosinophil counts 1. Without adequate cortisol, eosinophils accumulate in the bloodstream, leading to eosinophilia. Cortisol typically inhibits the release of interleukin-5 (IL-5) and other cytokines that stimulate eosinophil production and survival. Additionally, cortisol normally promotes eosinophil sequestration in lymphoid tissues and enhances their removal from circulation. The absence of these regulatory mechanisms in adrenal insufficiency allows for increased eosinophil counts.

Key Points

• Eosinophilia is a common finding in primary adrenal insufficiency, with mild eosinophilia present in approximately 10-20% of patients at presentation 1.
• The diagnosis of primary adrenal insufficiency requires assessment of adrenal cortex function, and laboratory findings such as hyponatremia, hyperkalemia, and increased plasma ACTH levels can support the diagnosis 1.
• Appropriate hormone replacement therapy, including daily oral hydrocortisone (typically 15-25 mg daily in divided doses) or prednisone (3-5 mg daily), along with fludrocortisone (0.05-0.2 mg daily) for mineralocorticoid replacement, can help resolve eosinophilia and improve patient outcomes 1.
• Monitoring complete blood counts during treatment can help confirm normalization of eosinophil levels as cortisol levels are restored.
• Patients with primary adrenal insufficiency require lifelong steroid replacement and education on how to increase steroid doses during concurrent illnesses or injury to prevent adrenal crisis 1.

From the Research

Increase in Eosinophils in Primary Adrenal Insufficiency

There is no direct evidence in the provided studies to explain the increase in eosinophils (white blood cells) in primary adrenal insufficiency (Addison's disease).

Adrenal Insufficiency Overview

• Adrenal insufficiency is characterized by inadequate glucocorticoid production due to destruction of the adrenal cortex or lack of adrenocorticotropic hormone stimulation 2.
• Primary adrenal insufficiency is caused by the failure of the adrenal gland, while secondary adrenal insufficiency is due to a lack of stimulation via pituitary adrenocorticotropic hormone or hypothalamic corticotropin-releasing hormone 3.
• The diagnosis of adrenal insufficiency is made by demonstrating low basal and/or stimulated serum cortisol, and should be followed by appropriate investigations to establish the underlying etiology 2, 3.

Management of Adrenal Insufficiency

• Maintenance glucocorticoid replacement is usually given as a twice or thrice daily hydrocortisone preparation, and patients with primary adrenal insufficiency also require mineralocorticoid replacement 2, 4.
• Regular monitoring for features of under- and over-replacement is essential during follow-up, and patient education is a key feature of management of this condition 2, 3.

Eosinophils in Adrenal Insufficiency

• Unfortunately, there are no research papers among the provided evidence to assist in answering the question about the increase in eosinophils in primary adrenal insufficiency.