When a person is experiencing stage fright, she sometimes suffers from uncontrollable shaking. The hands, knees, lips, and even voice starts to tremble, making it difficult for the person to proceed normally. Because the shaking is an involuntary reaction to the situation the person will find it difficult to stop, unless she calms her nerves or completes the task.
One other common sign of stage fright is a nauseous feeling in the pit of the stomach. Nausea is a common symptom of anxiety. So if a person complains of a queasy feeling in advance of entering the stage, that could just be a direct result of stage fright that will pass as the person gets comfortable in front of the audience.
Another symptom of stage fright is severe perspiration. A person suffering from stage fright may sweat profusely from common areas on the body, including his underarms, face and neck. His hands may also become sweaty due to his fear of presenting on-stage.
If a person's skin tone suddenly becomes paler, weak, or loses its red tint, that is a common sign of stage fright. Severe stage fright can cause the person's blood to temporarily leave his face and hands. This also causes the skin to become cold and clammy directly before a performance.
In some cases, a person may have a problem remembering what he must present, whether it's lines in a play or a speech, directly before the presentation. So if you notice that someone is panicking and can't recall even the simplest bit of content for the on-stage presentation, that could be a sign that he's suffering from stage right.