The most effective bed bug rash treatment for mild reactions involves applying corticosteroid cream to the bites, according to the American Academy of Dermatology. Lower-strength formulations of corticosteroid creams are available over the counter, but stronger forms of the medication require a doctor's prescription.
Treatment for an allergic reaction from bed bug bites often requires an injection of epinephrine, corticosteroid or an antihistamine, explains the American Academy of Dermatology. Bed bug rashes that develop an infection may require an antiseptic medication or prescription antibiotics to eliminate bacteria from the body. Extreme itching from a bed bug rash can be treated with an antihistamine.
Individuals showing no signs of a serious reaction or infection can treat minor beg bug bites at home by washing the affected skin with soap and water to prevent a skin infection and applying over-the-counter corticosteroid cream to alleviate itching, according to the American Academy of Dermatology.
Bed bug bites and rashes typically decrease in size or disappear within one or two weeks, according to the American Academy of Dermatology. Bed bug bites can be detected by their appearance. The bites and rashes develop welts and a zigzag pattern on the skin, with the welts often causing intense itching.