In Raynaud’s disease true is :a) Lower limb more involved than commonly upper limbb) More common in femalec) Sup. thrombophlebitisd) Associated with migraine

**Core Concept**
Raynaud's disease is a vasospastic disorder characterized by episodic vasospasm of the digital arteries, leading to reduced blood flow to the fingers and toes. This condition is often triggered by exposure to cold temperatures or emotional stress, resulting in transient ischemia and subsequent tissue damage.

**Why the Correct Answer is Right**
The correct answer is **b) More common in females**. This is because Raynaud's disease has a strong female predilection, with a female-to-male ratio of approximately 3:1 to 4:1. The exact etiology is unclear, but hormonal influences and autoimmune factors are thought to contribute to the increased susceptibility in females. The condition often presents with a typical pattern of vasospasm, involving the fingers, toes, or both, in response to cold temperatures or emotional stress.

**Why Each Wrong Option is Incorrect**
**Option A:** Lower limb involvement is less common than upper limb involvement in Raynaud's disease, as the condition typically affects the fingers and toes, with the fingers being more frequently affected.

**Option C:** Sup. thrombophlebitis is not a characteristic feature of Raynaud's disease. Thrombophlebitis refers to inflammation of a vein, often due to a blood clot, whereas Raynaud's disease is a vasospastic disorder.

**Option D:** While some patients with Raynaud's disease may also experience migraines, there is no direct association between the two conditions. Migraines are a separate entity, characterized by recurrent episodes of headache, often accompanied by nausea, vomiting, and sensitivity to light and sound.

**Clinical Pearl / High-Yield Fact**
Raynaud's disease is often associated with other autoimmune disorders, such as systemic lupus erythematosus (SLE), scleroderma, and rheumatoid arthritis. A high index of suspicion for these conditions should be maintained in patients with Raynaud's disease, particularly if they have additional systemic symptoms.

**Correct Answer:** b) More common in females.