Which of the following would be symptoms of severe OLEA poisoning in a child?

Severe OLEA (oleander plant) poisoning is particularly dangerous and can lead to significant neurological and systemic effects. Convulsions, or seizures, are a critical symptom of this type of poisoning as they indicate severe central nervous system involvement. The toxic compounds in oleander can disrupt normal brain function and lead to seizures, which is a life-threatening manifestation of toxicity.

While headache and skin rash may occur in less severe cases, they are not definitive indicators of severe poisoning. Blisters on the skin can also occur due to other causes and are not typically associated with OLEA poisoning specifically. Therefore, the presence of convulsions is particularly alarming and signifies that urgent medical attention is needed, making it the primary symptom to be aware of in cases of severe OLEA poisoning in children.