Immunoglobulin IgE

Function

Immunoglobulin E (IgE) is a class of antibodies produced by the immune system that plays a central role in the body's allergic response. It is typically found in very small amounts in the blood. IgE binds to mast cells and basophils; when it encounters an allergen (like pollen or dander), it triggers these cells to release histamine and other chemicals, causing allergic symptoms.

Why it is Ordered

Total IgE testing is used as a screening tool to assess a person's 'allergic status.' It is ordered for patients suffering from chronic asthma, hay fever, eczema (atopic dermatitis), or persistent hives. It is also a critical diagnostic tool when a parasitic infection is suspected, as IgE levels often rise significantly as the body attempts to fight off helminths (worms).

Associated Conditions

• Allergic Rhinitis and Asthma: High levels are common in individuals with seasonal or perennial allergies.
• Atopic Dermatitis: Severe eczema is often associated with very high total IgE.
• Parasitic Infections: Elevations occur in response to parasites like hookworm or Ascaris.
• Hyper-IgE Syndrome (Job's Syndrome): A rare genetic disorder characterized by extremely high IgE levels and recurrent skin/lung infections.
• Allergic Bronchopulmonary Aspergillosis (ABPA): A serious allergic reaction to the fungus Aspergillus.