A 22 year old woman developed small itchy wheals after physical exertion, walking in the sun, eating hot spicy food and when she was angry. The most likely diagnosis is –
**Core Concept**
The patient's symptoms are suggestive of a condition that involves the release of histamine from mast cells, leading to increased capillary permeability, smooth muscle contraction, and vasodilation. This condition is often triggered by physical stimuli, emotional stress, or certain food items.
**Why the Correct Answer is Right**
The patient's symptoms, such as itchy wheals, are characteristic of urticaria, a condition that involves the release of histamine from mast cells. The mast cells release histamine in response to various stimuli, including physical exertion, heat, cold, sunlight, and emotional stress. The histamine released causes vasodilation, increased capillary permeability, and smooth muscle contraction, leading to the characteristic symptoms of urticaria.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because, while it's a common skin condition, eczema (atopic dermatitis) typically presents with dry, scaly, itchy skin, and is not typically triggered by physical stimuli or emotional stress.
**Option B:** This option is incorrect because, while it's a type of skin rash, contact dermatitis is typically caused by exposure to allergens or irritants, and is not characterized by the widespread itchy wheals seen in this patient.
**Option C:** This option is incorrect because, while it's a type of skin rash, impetigo is typically caused by bacterial infection, and is not characterized by the itchy wheals seen in this patient.
**Clinical Pearl / High-Yield Fact**
Urticaria can be divided into two types: acute (lasting less than 6 weeks) and chronic (lasting more than 6 weeks). Acute urticaria is often caused by an allergic reaction, while chronic urticaria is often caused by autoimmune or other underlying conditions.
**Correct Answer:** D.