What's the best treatment to get rid of abdominal skin itching?

OTC oral/topical: Skin itch can be treated with topical Cortaid (or any generic Hydrocortisone 1% cream) and/or oral anti-histamines (benedryl, zytrec, allegra, claritin (loratadine)...). Be careful with chronic use of topical steroids: use for short periods of time to prevent skin atrophy ('thinning of the skin'). Get seen if not improved.

Find the cause first: You can control the itch with daily non-sedating antihistamines tablets. If the regular dose doesn't help. Fexofenadine, Loratadine and Cetirizine have been studied upto twice a day to control severe hives. Using a topical cream with 1% Hydrocortisone may also help. Use cetaphil lotion as a bathing "soap". Do not use any other soaps, creams or lotions. If this doesn't help see your primary doctor.