Some medications (vancomycin, morphine, x-ray contrast among others) cause anaphylaxis by directly triggering mast cell degranulation.The frequency of a reaction to an agent partly depends on the frequency of its use and partly on its intrinsic properties. Anaphylaxis to penicillin or cephalosporins occurs only after it binds to proteins inside the body with some agents binding more easily than others. Anaphylaxis to penicillin occurs once in every 2,000 to 10,000 courses of treatment, with death occurring in fewer than one in every 50,000 courses of treatment. Anaphylaxis to aspirin and NSAIDs occurs in about one in every 50,000 persons. If someone has a reaction to penicillin, his or her risk of a reaction to cephalosporins is greater but still less than one in 1,000. The old radiocontrast agents caused reactions in 1% of cases, while the newer lower osmolar agents cause reactions in 0.04% of cases. Venom
Venom from stinging or biting insects such as Hymenoptera (ants, bees, and wasps) or Triatominae (kissing bugs) may cause anaphylaxis in susceptible people. Previous reactions that are anything more than a local reaction around the site of the sting, are a risk factor for future anaphylaxis; however, half of fatalities have had no previous systemic reaction. Risk factors
People with atopic diseases such as asthma, eczema, or allergic rhinitis are at high risk of anaphylaxis from food, latex, and radiocontrast agents but not from injectable medications or stings.
Reflex seizures are epileptic seizures that are consistently induced by a specific stimulus or trigger making them distinct from other epileptic seizures, which are usually unprovoked. Reflex seizures are otherwise similar to unprovoked seizures and may be focal (simple or complex), generalized, myoclonic, or absence seizures. Epilepsy syndromes characterized by repeated reflex seizures are known as reflex epilepsies. Photosensitive seizures are often myoclonic, absence, or focal seizures in the occipital lobe, while musicogenic seizures are associated with focal seizures in the temporal lobe.Triggers may include various stimuli with the most common (75 to 80%) being flickering lights resulting in photosensitive seizures. Reflex epilepsies are generally thought to be genetic in origin. The inheritance pattern is dependent on the type of reflex epilepsy with some types lacking a specific genetic inheritance patterns. For example, photogenic epilepsy is thought to follow an autosomal dominant pattern with incomplete penetrance, while seizures triggered by proprioceptive stimuli do not follow an observable inheritance pattern. The underlying mechanism involves the stimulation of existing network of neurons by the specific trigger.The treatment of reflex epilepsy generally involves decreasing exposure to a persons triggers as well as anti-epileptic medications. Reflex epilepsy is relatively rare, making up approximately 5% of epilepsy syndromes. Signs and symptoms
Reflex seizures can be either generalized or focal seizures or both. However, for any given stimulus there may be a large variation in the kind of elicited seizure.