Allergic reaction to laundry detergent. I have a terrible rash and can't sleep. I get severe akathisia from antihistamines. What else can I take?

Detergent reaction. You can try OTC topical hydrocortisone 1% cream. Akathesia, although very rare, may occur with first generation antihistamines as diphenhydramine (Benadryl) , hopefully not the case with the newer less sedating as loratadine or desloratadine, as for your akathesia vs RLS, I believe you need to see an experienced neurologist for assessment, best wishes.