Quick Answer: Secondary service connection allows you to get VA compensation for a new condition that was caused or aggravated by an already service-connected disability. You do not need to trace the new condition back to your military service directly — only to a condition already on your record.

What Is Secondary Service Connection?

Under 38 CFR § 3.310, a disability that is proximately due to or the result of a service-connected condition shall be service connected as a secondary condition. This means conditions that developed after military service — and would normally be denied — can still be rated if they were caused by something already on your service-connected record.

Common Secondary Service Connection Chains

Here are common, medically established secondary chains:

• Lower back pain → radiculopathy: A service-connected lumbar spine condition causing radiating nerve pain in the legs
• Tinnitus → anxiety or depression: Chronic tinnitus causing or aggravating mental health conditions
• Knee injury → hip pain: Altered gait from a service-connected knee condition causing secondary hip degeneration
• PTSD → sleep apnea: Service-connected PTSD-related sleep disruption progressing to sleep apnea
• Diabetes → peripheral neuropathy, kidney disease, erectile dysfunction: Diabetes secondary to herbicide exposure (Agent Orange) causing multiple downstream conditions
• Medication side effects: Conditions caused by medications prescribed for service-connected conditions

How to File a Secondary Service Connection Claim

File VA Form 21-526EZ and clearly state that you are claiming the new condition as secondary to [your existing service-connected condition]. You will need:

• A current diagnosis of the secondary condition
• A nexus letter or medical opinion establishing the causal link between your service-connected condition and the new diagnosis
• Medical records documenting both conditions

Aggravation vs. Causation

The VA recognizes two types of secondary service connection. Causation means the service-connected condition directly caused the new condition. Aggravation means your service-connected condition made a pre-existing non-service-connected condition worse. Both qualify for secondary service connection under 38 CFR § 3.310.

You should work with a VA-accredited VSO when building secondary claims. These are often the most documentation-intensive claims, and accredited VSOs can help you identify the strongest secondary chains and obtain the supporting evidence needed — at no cost to you under federal law and California SB 694.

Frequently Asked Questions

Can I claim unlimited secondary conditions?

Yes. There is no cap on secondary claims. Every service-connected condition can potentially serve as a basis for additional secondary claims if the medical evidence supports the link.

Do I need a nexus letter for every secondary claim?

Not always — for well-established medical relationships (like lower back pain causing radiculopathy), strong medical records alone may be sufficient. For less obvious links, a nexus letter from a physician significantly strengthens the claim.