Prognosis
Generally, PLE resolves without treatment; also, PLE irritations generally leave no scar.There may be a possible link with autoimmune thyroid disease. Some progression to autoimmune disease has been observed. However, another study of people with elevated titres of antinuclear antibodies with PLE found no progression to lupus erythematosus after an 8-year follow-up. Epidemiology
In the United States, whilst one-quarter of people being investigated for a photosensitivity disorder were diagnosed with PLE, the prevalence in the general population is 10 to 15% and may even be as high as 40% as suggested in one study of more than 2000 people. It is also particularly more prevalent in Central Europe and Scandinavia.PLE is more common in young adults and has a female preponderance with a ratio of 2:1 female-to-male. In Germany the female to male ratio has been cited as 9:1. It can, however, occur in all age groups and all skin types.Those experiencing sun exposure all year round seldom acquire PLE eruption. Hence, it is less common near the equator.The cases of this condition are most common between the spring and autumn months in the northern hemisphere and at higher altitudes. Society and culture
Reports of psychological distress have been made in more than 40% of peoples with PLE.
For example, if the atria are electrically activated at 300 beats per minute, half those electrical impulses may be blocked by the AV node, so that the ventricles are stimulated at only 150 beats per minute – resulting in a pulse of 150 beats per minute. Another important property of the AV node is that it slows down individual electrical impulses. This is manifested on the electrocardiogram as the PR interval (the time from electrical activation of the atria to electrical activation of the ventricles), which is usually shortened to less than 120 milliseconds in duration.Individuals with WPW have an accessory pathway that communicates between the atria and the ventricles, in addition to the AV node. This accessory pathway is known as the bundle of Kent. This accessory pathway does not share the rate-slowing properties of the AV node and may conduct electrical activity at a significantly higher rate than the AV node. For instance, in the example above, if an individual had an atrial rate of 300 beats per minute, the accessory bundle may conduct all the electrical impulses from the atria to the ventricles, causing the ventricles to contract at 300 beats per minute. Extremely rapid heart rates such as this may result in hemodynamic instability or cardiogenic shock. In some cases, the combination of an accessory pathway and abnormal heart rhythms can trigger ventricular fibrillation, a leading cause of sudden cardiac death.WPW may be associated with PRKAG2, a protein kinase enzyme encoded by the PRKAG2 gene.