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How Pre-Existing Conditions Affect Your Injury Claim
If you had a pre-existing condition before your accident, the insurance company will try to use it against you. But California law protects you. This article explains how a pre-existing conditions injury claim works, what the eggshell plaintiff rule means for your case, and how to build strong evidence that separates old symptoms from new damage.
How Pre-Existing Conditions Affect Your Injury Claim
One of the first things an insurance adjuster will look for after your accident is a reason to pay you less. And if you have a pre-existing condition, they just found their favorite excuse. A pre-existing conditions injury claim is where things get messy fast, because the insurance company is banking on you not knowing how the law actually works here.
Let’s get this out of the way early. Having a pre-existing condition does not disqualify you from getting compensation. Not in California, not even close. But the way the insurance company talks about it, you’d think a bad back from five years ago means the accident didn’t matter. That’s not how it works, and it’s not what the law says.
What Is the Eggshell Plaintiff Rule?
California follows what’s called the eggshell plaintiff rule. The name sounds a little strange, but the concept is simple. If someone is more vulnerable to injury because of a pre-existing condition, the person who caused the accident is still fully responsible for all the harm they caused. Even if a perfectly healthy person would have walked away fine. You take your victim as you find them. That’s the rule.
So if you had mild arthritis in your knee before the crash and now you can barely walk, the at-fault driver doesn’t get a discount because your knee wasn’t perfect to begin with. They’re responsible for the difference between where you were and where you are now. That gap is your claim.
Understanding the Difference Between Aggravation and Causation
This is where the legal details actually matter to your case, so it’s worth slowing down here.
There’s a big difference between an accident causing a brand new injury and an accident making an existing condition worse. Both are compensable in California, but they get argued differently.
Aggravation of a Pre-Existing Condition
If the accident aggravated your pre-existing condition, you’re entitled to compensation for the aggravation. Meaning the additional pain, the new limitations, the extra treatment you now need that you didn’t need before. The insurance company doesn’t get to blame the whole thing on your prior condition. They only get to argue about what was already there versus what the accident added.
Here’s where it gets tricky though. If you weren’t actively treating the condition before the accident, insurers love to claim you were fine and the accident didn’t really change anything. On the flip side, if you were actively treating it, they’ll argue everything you’re feeling now is just a continuation of what you already had. They play both sides, and that’s exactly why documentation matters so much.
What the Insurance Company Will Try to Do
Let’s not pretend this is a fair process. Insurance adjusters have a playbook for pre-existing conditions injury claims and they use it aggressively. Here’s what you’re likely to run into:
- They will request your full medical history. Not just the records from after the accident. They want years of records, sometimes going back a decade or more, looking for anything they can use to argue your current symptoms existed before the crash.
- They will cherry-pick old complaints. Found a note from 2019 where you mentioned occasional lower back stiffness to your doctor? That’s now their evidence that your herniated disc wasn’t caused by the rear-end collision. Never mind that occasional stiffness and a herniated disc are completely different things.
- They will use your own words against you. If you told the ER doctor “I have a history of back problems,” that one sentence shows up in every denial letter. Even if what you meant was you threw your back out once moving furniture three years ago.
- They will lowball the settlement. The whole point of bringing up your pre-existing condition is to reduce what they pay. They’ll try to attribute as much of your treatment as possible to the old condition, not the accident.
How to Protect Your Pre-Existing Conditions Injury Claim
Knowing what the insurance company is going to do gives you a head start. There are concrete steps you can take to build a strong case even with a pre-existing condition on your medical record.
Get a Clear Medical Opinion
The most important thing is getting a clear medical opinion from your treating doctor. You need your physician to clearly state, in writing, what changed after the accident. Not just that you’re in pain now, but specifically how the accident worsened your condition compared to where you were before. Doctors call this an aggravation opinion, and it can make or break your case.
Be Honest About Your Medical History
Be completely honest with your medical providers about your history. This sounds counterintuitive because you might think hiding old injuries helps your case. It absolutely does not. If the insurance company finds out you weren’t upfront about a pre-existing condition, they’ll use that to question your credibility on everything else. Tell your doctors the truth. They can still document that the accident made things significantly worse.
Establish Your Baseline Before the Accident
Keep a record of your baseline before the accident. This is easier if you were seeing a doctor regularly, because those records show what your normal was. If your pre-existing condition was managed and stable, and now it’s debilitating, that contrast tells a powerful story. Even if you weren’t in regular treatment, think about what you could do before versus what you can do now:
- Could you work full days without pain?
- Were you able to play with your kids or exercise regularly?
- Could you sleep through the night?
- Were you living independently without needing help for daily tasks?
That before-and-after comparison matters more than almost anything else in these cases.
Organize Your Documentation
The more detailed and consistent your records are, the harder it is for an insurer to twist the narrative. Make sure you have:
- Medical records from before and after the accident
- Therapy notes and prescription history
- Imaging studies showing changes (MRI, X-ray, CT scan)
- Notes from your doctors about how your condition changed post-accident
The Eggshell Plaintiff Rule in Real Life
The eggshell plaintiff doctrine isn’t just some obscure legal theory. It comes up all the time in California personal injury cases, and it’s one of the strongest protections available in a pre-existing conditions injury claim.
Say you had a previous neck surgery and the accident caused a re-injury that now requires a second surgery. The at-fault driver’s insurance has to cover that second surgery, even though a person without your surgical history might not have needed it. Your vulnerability doesn’t reduce their liability.
Or maybe you have a degenerative disc condition that was mostly asymptomatic before the crash. You were living your life, going to work, no real complaints. Then the accident accelerated the degeneration by years and now you’re facing spinal injections or fusion surgery. That acceleration of a pre-existing condition is fully compensable. The insurance company pays for where you are now compared to where you would have been without the accident.
This rule exists because it would be deeply unfair to penalize someone for being human. Everyone has some level of wear and tear on their body. Older adults, people with prior injuries, individuals managing chronic conditions. They don’t deserve less justice because they weren’t in perfect health when someone else caused an accident.
Why Timing and Legal Help Matter
Pre-existing condition cases are more complex than a straightforward injury claim. There are more moving parts, more records to gather, and more arguments the insurance company will throw at you. The statute of limitations still applies, two years from the date of the accident in California, and these cases take time to build properly.
Getting legal guidance early gives your attorney time to collect the right medical opinions, organize your treatment history, and build the narrative that separates what was already there from what the accident caused. That distinction is everything in a pre-existing conditions injury claim, and it’s not something you want to figure out on your own while the insurance company is already building their case against you.
A Pre-Existing Condition Should Not Cost You Fair Compensation
If an accident made your condition worse, you have every right to pursue a claim. Pyramid Legal helps clients with complex injury cases build the evidence that separates old symptoms from new damage.
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Frequently Asked Questions
Yes. California's eggshell plaintiff rule protects people with pre-existing conditions. If an accident aggravated or worsened a condition you already had, the at-fault party is responsible for that additional harm. Having a prior injury or medical condition does not disqualify you from pursuing compensation for what the accident made worse.
The eggshell plaintiff rule means that the person who caused the accident is responsible for all harm they caused, even if the victim was more vulnerable due to a pre-existing condition. The defendant cannot argue that a healthier person would not have been hurt as badly. California law requires them to take the victim as they find them.
Insurance companies routinely request extensive medical records to find pre-existing conditions they can use to minimize your claim. They may cherry-pick old complaints, argue your symptoms existed before the accident, or try to attribute your current treatment to a prior condition. Having a clear medical opinion that documents what changed after the accident is the strongest way to counter these tactics.
