Secondary Raynaud’s phenomenon is caused by an underlying condition or factor that triggers the characteristic blood vessel spasms leading to reduced blood flow, typically in the fingers and toes. Common causes include:

1. Autoimmune Diseases: Conditions like systemic sclerosis (scleroderma), lupus (systemic lupus erythematosus), rheumatoid arthritis, or Sjögren’s syndrome are frequent culprits, as they can damage blood vessels or cause inflammation.
2. Vascular Diseases: Disorders such as atherosclerosis, Buerger’s disease, or pulmonary hypertension can impair blood vessel function, contributing to Raynaud’s.
3. Medications or Substances: Drugs like beta-blockers, chemotherapy agents (e.g., cisplatin), or stimulants (e.g., amphetamines) can constrict blood vessels. Overuse of nicotine or exposure to certain chemicals (e.g., vinyl chloride) may also play a role.
4. Nerve Disorders: Conditions affecting nerve control of blood vessels, such as carpal tunnel syndrome or thoracic outlet syndrome, can trigger symptoms.
5. Infections or Malignancies: Certain infections (e.g., hepatitis B or C) or cancers (e.g., leukemia) can lead to vascular changes associated with secondary Raynaud’s.
6. Trauma or Injury: Repetitive stress (e.g., using vibrating tools), frostbite, or direct vascular injury can damage blood vessels, causing symptoms.
7. Endocrine Disorders: Hypothyroidism or other hormonal imbalances may affect blood flow regulation.

Unlike primary Raynaud’s, which is idiopathic and not linked to another condition, secondary Raynaud’s is often more severe and associated with tissue damage or complications due to the underlying disease. Diagnosis typically involves identifying the root cause through medical history, physical exams, and tests like blood work or imaging.

Disclaimer: owerl is not a doctor; please consult one.