In most cases this would involved providing information about the symptoms suffered as a result of the condition. However in the recent case of Dryden and others v Johnson Matthey Plc  UKSC 18 the Supreme Court considered a situation where a condition did not cause any symptoms for the claimants.
Background to the case
The case involved claims by several individuals who had been exposed to platinum salts due to the failure by their employers to ensure that the factories in which they worked making catalytic converters were properly cleaned. As a result of the exposure the individuals had developed platinum salt sensitisation. This is symptomless but there is a risk that suffers will develop an allergic reaction if they are further exposed to the salts. The allergic reaction could have symptoms such as asthma or other bronchial problems, running eyes or nose, skin irritations or rashes.
The individuals wanted the court to award them damages for financial losses they had suffered as a result of having developed the sensitisation. The sensitisation had been detected by routine skin tests carried out by their employers. The losses arose because, once the sensitisation was detected, the individuals were prohibited from working in areas where they might suffer further exposure to the salts so they had to either (i) take different jobs or (ii) have their employment terminated.
When the case first came before a court the judge held that the sensitisation was not a personal injury. Accordingly the individuals were not entitled to any award because what they were looking for was classed as "pure economic loss" which was not recoverable. At the first appeal of the case the Court of Appeal agreed.
The Supreme Court's conclusion
The Supreme Court disagreed with the earlier courts and held that the individuals had suffered a personal injury. In reaching this view, it was relevant that the behaviour of an antibody within the individual was changed as a result of the sensitisation meaning that if they were further exposed to the salts they were likely to develop an allergy. This change to the person's body meant that their ordinary life was affected because they could not then keep doing a job of the type which they normally did. It did not matter to the court that the sensitisation itself was symptomless.
Contrast with plural plaques cases
At first glance, this situation in this case might seem similar to the situation of those who are suffering from plural plaques. This was something which was considered by the court when it was looking at the decision of the House of Lords in the Rothwell v Chemical & Insulating Co Ltd  AC 281 which the defendants had referred to when arguing that the sensitisation should not be classified as a personal injury.
The court reached the view, after considering the expert medical evidence which had been led, that the facts of this case were distinguishable from a situation where an individual had developed plural plaques. Plural plaques were a marker of exposure to asbestos dust which were symptomless in themselves and not leading or contributing to any condition which would produce symptoms, even if the sufferer were to be exposed to further asbestos dust (the risk was the presence of asbestos and not the presence of the plural plaques). In contrast, the sensitisation which arose in this case constituted a change to the individuals physiological make-up which meant that further exposure carried the risk of an allergic reaction and for that reason the individuals must change their everyday lives so as to avoid any further exposure.
The distinction with plural plaques cases is, of course, not of the same relevance in Scotland because the Damages (Asbestos-related Condition) (Scotland) Act 2009 reversed the effect of the Rothwell decision in Scotland.
So what does this case added to the test for confirming whether a particular condition can be classified as an actionable personal injury for the purpose of court action?
The Supreme Court said it was worth noting at the outset that nowhere in the authorities they were looking at was there a definition of personal injury although there was some guidance as to the attributes of it. They also noted that the term was often referred to in legislation sometimes without definition or sometimes, as in the Limitation Act 1980 as "any disease and any impairment of a person's physical or mental condition" (which is the same as the definition in the Prescription and Limitation (Scotland) Act 1973).
When summarising the authorities the court noted that, as well as the usual reference to "pain, suffering and loss of amenity", personal injury has been seen as a physical change which makes the claimant appreciably worse off in respect of his "health or capability". It could include injury sustained to a person's "physical capacity of enjoying life" and also an "impairment". It could also be hidden and symptomless.
Whether or not an injury suffered will be an actionable personal injury will depend very much on the facts of the injury suffered and the impact, or potential impact, which it can have. This case shows that an injury which prevents a claimant from carrying out a particular form of employment can constitute an actionable personal injury even although it is symptomless.