Cutaneous hypersensitivity

Definition

Cutaneous hypersensitivity is an exaggerated immune response occurring in the skin, typically manifested as inflammation, redness, or itching when exposed to specific allergens or irritants. This hypersensitivity can involve various immune cells, such as T cells and mast cells, and is often associated with conditions like allergic contact dermatitis and atopic dermatitis.

5 Must Know Facts For Your Next Test

1. Cutaneous hypersensitivity reactions can be classified into different types, such as immediate (Type I) and delayed (Type IV) hypersensitivity, affecting the nature of the immune response.
2. Mast cells release histamine and other inflammatory mediators during cutaneous hypersensitivity reactions, which leads to symptoms like swelling, redness, and itching.
3. Common triggers for cutaneous hypersensitivity include substances like poison ivy, certain metals (like nickel), and specific medications.
4. The involvement of skin-associated lymphoid tissue (SALT) is crucial for initiating and regulating hypersensitivity responses in the skin.
5. Management of cutaneous hypersensitivity often includes avoiding known allergens and using topical or systemic corticosteroids to reduce inflammation.

Review Questions

• How does cutaneous hypersensitivity differ between immediate and delayed hypersensitivity reactions?
  • Cutaneous hypersensitivity can be categorized into immediate and delayed reactions. Immediate hypersensitivity occurs quickly after exposure to an allergen, typically within minutes, and is primarily mediated by IgE antibodies and mast cells, leading to symptoms like urticaria or anaphylaxis. Delayed hypersensitivity develops over several hours to days and involves T cells activating an inflammatory response without the involvement of antibodies, often seen in conditions like allergic contact dermatitis.
• Discuss the role of skin-associated lymphoid tissue (SALT) in the development of cutaneous hypersensitivity.
  • Skin-associated lymphoid tissue (SALT) plays a critical role in the immune response involved in cutaneous hypersensitivity. SALT contains various immune cells, including dendritic cells that capture allergens and present them to T cells. This interaction activates T cells, which then migrate to the site of exposure and contribute to inflammation. Thus, SALT acts as a vital component in both recognizing allergens and orchestrating the subsequent immune response that leads to hypersensitivity symptoms.
• Evaluate the impact of environmental factors on cutaneous hypersensitivity, considering both triggers and immune system responses.
  • Environmental factors significantly impact cutaneous hypersensitivity by introducing various allergens that can trigger immune responses. For instance, exposure to certain plants or chemicals can elicit immediate reactions in sensitized individuals. Additionally, factors like air pollution, climate change, and even skin microbiome composition can alter immune system responses, potentially increasing susceptibility or severity of hypersensitivity reactions. Understanding these dynamics is essential for developing strategies to manage and prevent cutaneous hypersensitivity effectively.

Related terms

Allergen: A substance that can provoke an allergic reaction in sensitive individuals, often leading to hypersensitivity responses.

Mast Cells:

A type of white blood cell found in connective tissues that plays a key role in allergic reactions by releasing histamine and other mediators.

T Cells: A type of lymphocyte that plays a central role in cell-mediated immunity, including the activation of immune responses in cutaneous hypersensitivity.