Environmental factors, such as cold winter weather, wind and dry indoor heat promote moisture loss from the skin, which can cause psoriasis symptoms to flare or worsen. If you have mild psoriasis, you might find that the regular use of a thick moisturizing product like petroleum jelly and hydrocortisone ointment helps to calm and protect your skin. The use of moisturizers can improve the skin barrier function by restoring hydration and forming a protective surface layer to guard against infection and irritants. Moisturizers also help to control scaling and dryness, and may even improve the associated itching. They should be applied immediately after bathing and several times during the day to maintain skin hydration levels. Your psoriasis can be further aggravated by stress, smoking or if you’re battling a cold or flu – all of which can contribute to weakening your immune system. See your doctor if you are experiencing difficulties in managing your psoriasis.