RBD associated with neurological disorders is frequently related to abnormal accumulation of alpha-synuclein, and more than 80% of patients with idiopathic RBD might develop Lewy body disease (LBD). Patients with narcolepsy are also more likely to develop RBD. The diagnosis is based on clinical history, including partners account and needs to be confirmed by polysomnography (PSG), mainly for its accuracy in differentiating RBD from other sleep disorders, since there is a loss of REM atonia with excessive muscle tone. However, screening questionnaires, such as RBDSQ, are also very useful for diagnosing RBD. Recurrent isolated sleep paralysis
Recurrent isolated sleep paralysis is an inability to perform voluntary movements at sleep onset, or upon waking from sleep. Although the affected individual is conscious and recall is present, the person is not able to speak or move. However, respiration remains unimpaired. The episodes last seconds to minutes and diminish spontaneously. The lifetime prevalence is 7%. Sleep paralysis is associated with sleep-related hallucinations. Predisposing factors for the development of recurrent isolated sleep paralysis are sleep deprivation, an irregular sleep-wake cycle, e.g. caused by shift work, or stress. A possible cause could be the prolongation of REM sleep muscle atonia upon awakening. Nightmare disorder
Nightmares are like dreams primarily associated with REM sleep. Nightmare disorder is defined as recurrent nightmares associated with awakening dysphoria that impairs sleep or daytime functioning. It is rare in children, however persists until adulthood. About 2/3 of the adult population report experiencing nightmares at least once in their life.
Tick-borne diseases like Rocky Mountain spotted fever produce a rash that may become extensive enough so as to be classified as exanthemous in as many as 90% of children with the disease. See also
List of cutaneous conditions

References
External links

Overview at About.com
Definition at MedTerms
Differential diagnosis
Dermatology Quiz Includes photo, diagnosis, and treatment of unilateral laterothoracic exanthem (ULE).