Do you have a photograph of the lesions that you are referring to?

Can you also elaborate on these:

• Age, gender and other relevant data of the patient.
• Duration of this condition.
• Any known illnesses that the patient has, like diabetes.

Most dermatological conditions may have increased itching in airconditioned rooms and cold environments as the air is generally dry in such areas. Dryness results in itchiness. (One exception probably is a condition called Urticaria calorica in which pruritus is seen in hot environments and after exercise alone, and is relieved by cold.)

Apart from that, the on-off nature of the lesions suggest that they are probably related to exposure to some allergen, either food or otherwise.

How to confirm? Most dermatological conditions related to allergy are based on history and the sense of observation and association of the patient. If the patient can relate the lesions and symptoms to a particular exposure, the diagnosis can be easy. Otherwise a battery of not-so-informative "allergy tests" may be required.