Final answer:
The skin acts as a barrier for the immune system and moisturizing creams contain ingredients like hyaluronic acid and ceramides that alleviate skin inflammation. Corticosteroid creams such as hydrocortisone treat symptoms of conditions like eczema but do not address the underlying cause.
Step-by-step explanation:
The skin, being an essential part of the innate immune system, functions as a physical, chemical, and biological barrier protecting against pathogens. Substances that are commonly found in moisturizing cream and have properties to alleviate itching and inflammation include hyaluronic acid, ceramides, dimethicone, and glycerin. These ingredients help to maintain the skin's hydration, barrier function, and integrity. Specifically, in cases like eczema, corticosteroid creams such as ones containing hydrocortisone are used to manage symptoms by suppressing the immune system reaction that causes inflammation, pruritus (itching), and rashes. However, these creams treat only the symptoms and do not address the underlying cause of the rash. Antihistamines and immunosuppressants are other treatments that target the immune response itself, aiming to reduce the allergic reaction.