**Core Concept**
Type I hypersensitivity, also known as immediate hypersensitivity, is a severe, allergic reaction that occurs within minutes of exposure to an allergen. This reaction is mediated by IgE antibodies, which trigger the release of histamine and other chemical mediators from mast cells, leading to symptoms such as hives, itching, swelling, and in severe cases, anaphylaxis.

**Why the Correct Answer is Right**
The correct answer involves the activation of mast cells, which release histamine and other chemical mediators. Histamine binds to H1 receptors on smooth muscle cells, causing vasodilation and increased permeability, resulting in the characteristic symptoms of type I hypersensitivity. The IgE antibodies play a crucial role in this process by cross-linking with allergen molecules and triggering the release of histamine.

**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because type IV hypersensitivity is a cell-mediated reaction that occurs over a longer period, typically 48-72 hours after exposure to an allergen.
* **Option B:** This is incorrect because type II hypersensitivity involves the binding of antibodies to cell surface antigens, leading to cell destruction, which is not characteristic of type I hypersensitivity.
* **Option C:** This is incorrect because type III hypersensitivity is an immune complex-mediated reaction that occurs over a longer period, typically hours to days after exposure to an allergen.

**Clinical Pearl / High-Yield Fact**
Type I hypersensitivity reactions are often unpredictable and can be life-threatening, making it essential to identify and avoid allergens that trigger these reactions. Common allergens include peanuts, tree nuts, fish, shellfish, milk, eggs, wheat, and soy.

**Correct Answer: D. Examples of type I hypersensitivity include allergic rhinitis, asthma, atopic dermatitis, and food allergies.**