Raynaud's phenomenon

Raynaud's phenomenon is an exaggerated narrowing of the small blood vessels of the fingers and toes in response to cold or emotional stress, briefly cutting off the blood supply. In a classic attack the affected digits go white (as the vessels clamp down), then blue (as the trapped blood loses oxygen), and finally red and often painful or tingly as the blood flows back. It is very common and usually harmless. The key distinction is between primary and secondary Raynaud's. Primary Raynaud's, the common form, occurs on its own — typically starting in younger people, affecting both hands symmetrically, without underlying disease or damage to the fingers. Secondary Raynaud's occurs as part of another condition, most importantly an autoimmune connective-tissue disease such as systemic sclerosis (scleroderma), lupus or mixed connective-tissue disease — where Raynaud's is often the first symptom, sometimes years before others. Features that suggest a secondary cause, and so warrant investigation, include onset later in life (over about 40), attacks affecting the fingers unevenly, sores or ulcers on the fingertips, or accompanying symptoms such as puffy fingers, skin thickening, joint pains or a rash. So while most Raynaud's is benign, the pattern and the company it keeps determine whether it needs looking into.

• Primary Raynaud's — the common, benign form; on its own, usually starting young, both hands.
• Autoimmune connective-tissue disease — scleroderma, lupus or mixed connective-tissue disease; often the first sign.
• Later-onset or one-sided attacks, or fingertip ulcers — features that point to a secondary cause.
• Certain medications — such as some beta-blockers and migraine drugs.
• Vibration or repetitive hand use — occupational.
• Smoking — worsens attacks.

Raynaud's is diagnosed from the description, but the important step is deciding whether it is primary (benign) or secondary to a connective-tissue disease. Blood tests help: an ANA is the key screen — a positive ANA, especially in a high titre, raises the possibility of a secondary cause and prompts specific antibodies (such as anti-Scl-70 for scleroderma, anti-U1-RNP for mixed connective-tissue disease). Inflammatory markers (ESR, CRP) and a full blood count may be checked. A specialist may also examine the tiny vessels at the nail folds (nailfold capillaroscopy). Mediora.AI can surface a positive ANA or a connective-tissue antibody from your results that shifts Raynaud's toward a secondary cause, but the assessment — especially with worrying features — belongs with your doctor or rheumatologist.