Legal Definitions - special-sensitivity rule

The special-sensitivity rule, also commonly known as the eggshell-skull rule, is a fundamental principle in personal injury law. It states that a defendant is responsible for all injuries they cause to a plaintiff, even if the plaintiff had a pre-existing condition or unusual vulnerability that made them more susceptible to harm than an "average" person.

In essence, the rule means that a defendant "takes the plaintiff as they find them." This prevents a defendant from arguing that they should not be fully liable for the extent of the harm simply because the plaintiff was unusually fragile or had a particular sensitivity that made their injuries worse than what a typical person might experience from the same incident.

Here are some examples illustrating this rule:

• Example 1: Physical Injury with Pre-existing Bone Condition

  Imagine a driver negligently rear-ends another car at a low speed. The impact is minor, causing only a slight jolt. However, the driver of the rear-ended car has a severe, undiagnosed case of osteoporosis, a condition that makes bones brittle. Due to this pre-existing vulnerability, the minor jolt causes several vertebral fractures.

  Under the special-sensitivity rule, the negligent driver is liable for the full extent of the spinal fractures, even though an average person might have only experienced a minor neck strain from the same impact. The driver cannot claim reduced liability because the victim had unusually fragile bones; they must "take the victim as they find them," including their pre-existing condition.

• Example 2: Emotional Harm with Pre-existing Mental Health Condition

  Consider a situation where a property owner's negligence leads to a security breach, resulting in a tenant being verbally threatened during a break-in, though not physically harmed. While most tenants might experience temporary distress, this particular tenant has a pre-existing anxiety disorder and develops severe, debilitating post-traumatic stress disorder (PTSD) as a direct result of the incident.

  The property owner cannot argue that they are only responsible for the "average" emotional distress a person would feel. Because of the special-sensitivity rule, the owner is liable for the full extent of the tenant's PTSD, as the tenant's pre-existing mental health vulnerability does not reduce the owner's responsibility for the harm caused by their negligence.

• Example 3: Chemical Exposure with Rare Allergy

  Suppose a cleaning company uses an unapproved, highly allergenic chemical in a public building, leaving trace residues. Most people would not react to such a small amount. However, a visitor with a rare and extreme allergy to that specific chemical suffers a severe anaphylactic shock, requiring emergency hospitalization and extensive medical treatment.

  The cleaning company cannot claim that the visitor's extreme allergic reaction was unforeseeable or that their liability should be limited because the visitor had an unusual sensitivity. The special-sensitivity rule dictates that the company is responsible for the full medical costs and suffering resulting from the anaphylactic shock, as they must take the visitor with all their individual sensitivities and vulnerabilities.