What is Delayed Type Hypersensitivity (DTH)?
Delayed Type Hypersensitivity (DTH) is a form of
immune response that occurs later, typically 24-72 hours after exposure to an antigen. Unlike immediate hypersensitivity reactions, DTH involves T cells rather than antibodies. This kind of hypersensitivity is an important aspect of the
immune system's defense mechanism, particularly against intracellular pathogens like mycobacteria, fungi, and certain parasites.
Pathophysiology of DTH
The pathophysiology of DTH involves the activation of
T cells, specifically CD4+ T helper cells. Upon encountering an antigen, these cells release cytokines, which recruit macrophages to the site of infection or antigen exposure. This leads to inflammation and tissue damage. The clinical manifestations of DTH can be seen in conditions such as contact dermatitis and the
tuberculin skin test, where the reaction is measured to assess exposure to Mycobacterium tuberculosis.
Clinical Manifestations
The clinical manifestations of DTH can vary but generally include redness, swelling, and induration at the site of antigen exposure. In the case of contact dermatitis, patients may experience itching, blistering, and scaling of the skin. In more severe cases, chronic exposure can lead to extensive skin changes and discomfort.Diagnosis
Diagnosis of DTH primarily involves clinical evaluation and history taking. Tests like the
patch test for contact dermatitis and the
Mantoux test for tuberculosis are commonly used. These tests help in identifying specific antigens that trigger the hypersensitivity reaction.
Management and Nursing Care
Management of DTH involves both pharmacological and non-pharmacological approaches. Corticosteroids and antihistamines may be used to reduce inflammation and alleviate symptoms. Nurses play a crucial role in educating patients about avoiding known allergens and irritants. Monitoring for signs of infection and providing appropriate wound care are also essential aspects of nursing care in patients with DTH.Patient Education
Educating patients about their condition is vital. Nurses should inform patients about the importance of avoiding triggers and following prescribed treatment plans. Patients should be taught how to recognize early signs of a DTH reaction and when to seek medical help. Additionally, educating patients on proper skin care and the use of emollients can help in managing chronic symptoms.Conclusion
Delayed Type Hypersensitivity (DTH) is a complex immune response that requires careful management and nursing care. By understanding the pathophysiology, clinical manifestations, and appropriate interventions, nurses can provide effective care and education to patients, helping them manage their condition and improve their quality of life.
