Chapter 18: Concepts of Care for Patients With Hypersensitivity (Allergy) and Autoimmunity

Hypersensitivity, commonly called allergy, represents an exaggerated immune reaction to an antigen the body has previously encountered, manifesting along a spectrum from mild symptoms to severe life-threatening emergencies. The four distinct types of hypersensitivity reactions each involve different immune mechanisms: Type I reactions are immunoglobulin E mediated and occur rapidly, producing conditions such as allergic asthma, allergic rhinitis, angioedema, and anaphylaxis; Type II reactions involve antibodies against cell-bound antigens, causing hemolytic transfusion reactions and drug-induced hemolytic anemia; Type III reactions result from immune complex deposition in tissues and include rheumatoid arthritis and systemic lupus erythematosus; Type IV reactions are T-cell mediated and delayed, encompassing contact dermatitis and tuberculin skin test responses. The chapter emphasizes angioedema as a severe Type I manifestation requiring immediate intervention, as well as anaphylaxis, the most critical allergic emergency demanding rapid epinephrine administration, supplemental oxygen, intravenous fluid resuscitation, and vigilant monitoring. Autoimmunity occurs when immune tolerance breaks down and the body attacks its own tissues; contributing factors include genetic predisposition, hormonal influences particularly estrogen, prior infections, and environmental triggers. Systemic lupus erythematosus serves as a major autoimmune exemplar, characterized by multisystem inflammation, immune complex deposition, and diverse clinical manifestations including the butterfly facial rash, photosensitivity, polyarthritis, profound fatigue, glomerulonephritis, and potentially serious cardiovascular and neurologic complications. Diagnosis relies on clinical presentation and laboratory confirmation through antinuclear antibody testing and anti-double-stranded DNA antibodies. Management involves corticosteroids as foundational therapy, immunosuppressive medications to prevent disease progression, hydroxychloroquine for cutaneous manifestations, and biologic agents targeting B-cell function. Nursing care encompasses patient education regarding ultraviolet light avoidance, infection recognition, medication adherence, and comprehensive psychosocial support addressing pain, fatigue, and emotional distress. The chapter also addresses Lyme disease, a tick-borne spirochete infection presenting with fever, fatigue, and characteristic erythema migrans rash, requiring prompt antibiotic intervention to prevent carditis, neurologic involvement, and chronic sequelae.