Dermatitis get worse during pregnancy?

I recently got very itchy all over the body from back, legs, arms, feet, hands and wherever I scratched it turns into red bumps or rash. I have some issue with small patches of skin allergy before but never the whole body like this, could pregnancy make it worse? I struggle to sleep and work, I used to take Antihistamine to help (Loratadine), can I do that?