It's surprising the number of people who still use soap on their skin. Be careful with soaps, which can be a harsh surfactant that indiscriminately removes good lipids as well as dirt and sebum. As explained earlier, this will thin the lipid (fatty) layer of the skin resulting in water escaping from the skin more rapidly, making it severely dry.
Use natural, gentle, fragrance-free products
Avoid products with sulphates, colours, artificial fragrances, harsh alcohols, phthalates and consider products that are specifically formulated for sensitive skin. New Zealand indigenous ingredients such as Kawakawa and Mamaku Fern are good ones to look out for.
Avoid exfoliators that have jagged edges, like apricot kernel, or walnut shell, as these scratch the skin and can be the cause of broken capillaries. Look for an exfoliator with natural and spherical beads that will buff away the dead skin cells.
Ingredients such as salicylic acid, glycolic acid, retinoid/retinol (Vitamin A), may all sound effective, but these are intense and can be too harsh. Look for ingredients that hydrate, replenish and retain moisture. A hydrating masque might be a good addition. Check the shelf-life of your products.
As our body ages, its processes slow down. This applies to the skin too, so the skin will naturally thin, therefore drying as well. If you've had oily skin at a younger age, you'll most likely (and happily) find that your skin will have started to produce less sebum. Unfortunately for those with dryer skin, it will become even more so. Try applying a serum prior to the moisturiser to dose the skin with deeper hydration.
The Immune System
If the body's immune system is not functioning correctly, it can misdirect itself to healthy tissues and can cause hypersensitivity and inflammation. Dry skin, eczema and/or a rash can be an example of this. Many rashes itch, such as those that often develop after an allergic reaction, but other rashes can be painful with no itching.
Patch test and take your time
Whilst it can be time consuming, you are best to patch test one product at a time. Give yourself 24 hours as some ingredients may take longer to react. Start under your neck or the inside of the arm, near the elbow, then proceed to the side of the face. Don't use more than one new product at a time, as if there is a reaction, you won't know which product is the cause. If you have reacted to a product, make sure you stop using it immediately. If it's extreme, seek medical advice.