Pre-Existing Conditions and the Eggshell Rule
A pre-existing condition is one of the most misunderstood parts of an injury claim. Many people assume that any prior back or neck trouble automatically sinks their case. It does not. In fact, having a prior condition cuts both ways — and Washington law treats different kinds of “pre-existing” situations very differently. Understanding those distinctions can change how your claim is viewed.
Disclaimer: This post is intended for general informational purposes only and does not constitute legal advice. For guidance specific to your situation, please consult with a qualified personal injury attorney.
A Prior Condition Cuts Both Ways
On one side, an insurer may point to a prior condition and argue that your current symptoms are just a continuation of something old rather than the result of the collision. That is the risk.
But on the other side, a prior condition can help explain your injuries. Someone whose body was already vulnerable may reasonably experience worse symptoms or a longer recovery after a crash than a person with no such history. The same history an insurer wants to use against you can also explain why the collision affected you the way it did.
Symptomatic Aggravation Versus a Historic, Dormant Condition
The most important distinction is between two very different situations that often get lumped together.
The first is an active aggravation: someone who is currently symptomatic — perhaps already in treatment — is injured in a crash and gets worse. The second is a historic condition that had gone quiet: someone had a problem in the past but was not experiencing symptoms in the days and weeks leading up to the collision.
These are not the same, and it is worth teasing them apart. If your intake paperwork simply says “history of neck pain,” the real question is whether that means something that flared up years ago and resolved, or something that was actively bothering you right before the crash. A period with no symptoms before the collision is strong evidence about your baseline and about causation. It does not make the prior condition legally vanish — the history still exists, and there is a recognized exception where care would have become necessary anyway through the natural progression of the condition, even without any trauma. But a genuine symptom-free stretch is powerful evidence that what you are dealing with now is new.
The Eggshell Rule
Washington follows what is often called the “eggshell plaintiff” rule: a defendant takes the injured person as they find them. If you were unusually susceptible to injury, and the collision caused you greater harm than it might have caused someone else, the at-fault party may be responsible for that greater harm.
It helps to be clear about what this rule does and does not do. It means a defendant cannot escape responsibility just because you were more fragile than average. It does not erase your prior condition, and it does not relieve you of the need to prove what the collision actually caused or aggravated. Susceptibility can genuinely help a case — prior injury to a tissue can leave it more vulnerable going forward — but it works alongside proof of causation, not as a substitute for it.
How Aggravation Cases Get Sorted Out
When a collision worsens a genuinely pre-existing, symptomatic condition, providers and lawyers look for ways to describe what the crash added on top of what was already there. This is a fact-specific medical and legal question, not a fixed formula — and it is not a mathematical division that has to be forced onto every case. Sometimes the causes can be told apart cleanly; sometimes they cannot.
Where the care can be separated by body part, that is often the clearest approach — if you had prior low-back trouble and the crash added new neck pain, the neck care is straightforwardly crash-related. For overlapping care, one approach assigns a percentage to the collision versus the prior condition, though rough percentages can be hard to justify and should be questioned when they are not grounded in objective findings. A more grounded approach treats the prior condition as a baseline and looks at the care needed to bring you from your worsened state back toward that baseline. There is a related pitfall worth knowing: an insurer may simply compare your treatment schedule before and after the crash and argue nothing changed. That is why it matters for the record to reflect how the care actually changed — different symptoms addressed, different methods used, a different focus. We discuss the mechanics further in “Understanding Apportionment in Personal Injury Claims.”
Final Thoughts
A pre-existing condition does not doom your claim. What matters is the distinction between an old, dormant issue and an active aggravation — and the honest work of showing what the collision caused or worsened. The eggshell rule means a defendant takes you as you are, but it does not do your proof for you.
If you have a prior condition and are worried about how it affects your claim, reach out to our team for a consultation. We help injured people throughout Washington sort out exactly these questions.
