Hello and welcome to healthcaremagic
I would keep a possibility of
Urticaria.
It presents as itching and skin welts/swellings, which can be localized Or distributed all over the body.
Certain factors like changes in body temperature as during a hot Or cold shower, Changes in ambient temperature like Cold Or Heat, Pressure(Prolonged Standing, Sitting), Scratching etc can lead to urticarial wheals. This type of urticaria is known as physical urticaria and is usually chronic.
An oral antihistamine like
Fexofenadine (Allegra 180 mg tab) OR
Loratadine (Alaspan 10mg tablet) once or twice daily for a week would be suitable. They are non-sedating and wont affect your alertness level.
For the present episode of urticaria, as a treating doctor I would have also given you a shot of injectable antihistamines like Avil(
pheniramine) and Injectable effcorlin(
hydrocortisone) for rapid relief.
A topical soothing lotion like calamine would help you symptomatically.
take care
regards