## **Core Concept**
Intrinsic asthma, also known as non-allergic asthma, is a subtype of asthma that is not driven by allergic reactions. It is characterized by the absence of high levels of IgE antibodies and a lack of atopic predisposition. This form of asthma often presents later in life and is not associated with a family history of allergies.

## **Why the Correct Answer is Right**
The correct answer can be deduced by understanding the characteristics of intrinsic asthma:
- **More severe & persistent (a):** Intrinsic asthma tends to be more severe and persistent compared to allergic (extrinsic) asthma. This is because intrinsic asthma often develops later in life and can be more resistant to treatment.
- **IgE normal (b):** In intrinsic asthma, IgE levels are typically normal, unlike in allergic asthma where IgE levels are elevated.
- **Family history +ve (c):** This is more characteristic of extrinsic (allergic) asthma. Intrinsic asthma does not have a strong familial allergic component.
- **Skin test positive (d):** Skin tests are usually negative in intrinsic asthma because it is not driven by allergic reactions, which are typically identified through positive skin prick tests.

## **Why Each Wrong Option is Incorrect**
- **Option C:** Family history +ve - This is incorrect for intrinsic asthma as it is more characteristic of extrinsic asthma.
- **Option D:** Skin test positive - This is incorrect because intrinsic asthma is not driven by allergic reactions, which would result in positive skin tests.
- **Option A & B** being part of the correct sequence implies their accuracy in describing intrinsic asthma.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that intrinsic asthma often presents in non-atopic individuals, without a family history of allergies, and with normal IgE levels. This form of asthma can be more challenging to manage due to its persistence and severity.

## **Correct Answer:** B.