Final answer:
Hot moist skin can increase the threshold of itch because sweat does not evaporate efficiently, leading to irritation and a heightened itch sensation. Moisturizing creams containing hydrating agents and emollients are used to alleviate this by hydrating the skin and reducing inflammation, especially in conditions like eczema.
Step-by-step explanation:
The relationship between hot moist skin and itching is that sweat does not evaporate efficiently on humid days, leading to a sensation of being hotter which can increase the threshold of itch. Hot moist skin provides a suitable environment for itch perception due to hydration and warmth. Under these conditions, one might experience heightened itchiness due to factors like increased sweat and potential irritation of the skin.
In terms of substances found in a moisturizing cream, one would expect to find hydrating agents such as glycerin, emollients like lanolin, and occlusives like petroleum jelly. These substances alleviate itching and inflammation by providing hydration, reinforcing the skin's barrier function, and reducing skin dryness, which can lessen the itchiness associated with conditions like eczema.
In the case of eczema, which is a dry, itchy rash that can swell and flake, managing symptoms often involves using moisturizers to hydrate skin, corticosteroid creams to reduce inflammation, and immunosuppressants to modulate the allergic response. Sufferers of eczema are encouraged to keep their skin moisturized to manage the itchiness and inflammation.