Human photosensitivity: from pathophysiology to treatment.

Photosensitivity is a condition detected on the electroencephalography (EEG) as a paroxysmal reaction to Intermittent Photic Stimulation (IPS). This EEG response, elicited by IPS or by other visual stimuli of daily life, is called Photo Paroxysmal Response (PPR). PPRs are well documented in epileptic and non-epileptic subjects. Photosensitivity rarely in normal individuals evolves into epilepsy. Photosensitive epilepsy is a rare refex epilepsy characterized by seizures in photosensitive individuals. The development of modern technology has increased the exposition to potential seizure precipitants in people of all ages, but especially in children and adolescents. Actually, videogames, computers and televisions are the most common triggers in daily life of susceptible persons. The mechanisms of generation of PPR are poorly understood, but genetic factors play an important rule. The control of visually induced seizures has, generally a good prognosis. In patients known to be visually sensitive, avoidance of obvious source and stimulus modifications are very important and useful to seizure prevention, but in the large majority of patients with epilepsy and photosensitivity antiepileptic drugs are needed.

Skin reactions due to anti-epileptic drugs: several case-reports with long-term follow-up.

In this study, the clinical findings and management of allergic skin reactions induced by the most used antiepileptic drugs, Lamotrigine (LMT) and Carbamazepine (CBZ), were evaluated. Lamotrigine is an antiepileptic drug recently released in several countries; it is effective for a variety of seizure types in adults and children, both as an add-on agent and in monotherapy, and it is generally well tolerated. Clinical and epidemiologic evidence suggest serious cutaneous reactions to antiepileptic drugs are more likely to occur during the first 8 weeks and they appear to increase when drugs are administered with other anticonvulsants, such as Valproate (VPA). We selected 10 patients who presented an idiosyncratic skin rash when treated with carbamazepine (8 patients) and lamotrigine (2 patients) administered as monotherapy, and we followed up on these patients for several years. Seven reactions were mild/severe cutaneous eruptions; one Toxic Epidermal Necrolysis, a case of Stevens-Johnson and a case of Hypersensitivity Syndrome. All severe skin drug reactions were induced by Carbamazepine. In five patients the AEDs were ceased abruptly (sometimes with the administration of a different molecule), tapered in four and continued unchanged in one. We conclude that the discontinuation of the drug with substitution with another is the most effective treatment and that corticosteroids are helpful in mild cutaneous reactions, while in severe skin reactions, such as Toxic Epidermal Necrolysis, corticosteroids are only a complementary therapy since intravenous immunoglobulins are the first choice treatment.

Photoparoxysmal responses in non-epileptic children in long-term follow-up.

OBJECTIVES: To evaluate the photoparoxysmal responses (PPR) in non-epileptic children and adolescents in long-term follow-up. MATERIALS AND METHODS: We studied 14 non-epileptic children who showed PPR without any other electroencephalographic (EEG) abnormalities. RESULTS: One subjects was lost after 1 year of follow-up. At the final follow-up, four of the 13 patients (approximately 30%) did not show any PPR or other epileptic discharges, while in other children PPR continued to be present. The age of the disappearance of PPR in these four patients ranged from 1.1 to 5.9 years from the first evaluation. No patients suffered from epileptic seizures during the whole period of follow-up. CONCLUSION: Our study confirms that PPR can be present in the EEG of non-epileptic children and adolescents and demonstrates that this EEG change is not related to the presence of seizures and must not be considered a marker for the developing of epilepsy.