Expired makeup can have a significant impact on older skin, which is often more delicate and susceptible to damage. Here's how:

1. **Increased Risk of Infections:** The preservatives in makeup that inhibit bacterial growth lose their effectiveness over time. This can lead to an increased risk of skin infections, which can be more severe in older adults due to a weakened immune system.

2. **Irritation and Inflammation:** As makeup ages, it can break down into harmful compounds that cause skin irritation and inflammation. This can be particularly problematic for older skin, which is thinner and less able to protect itself from irritants.

3. **Allergic Reactions:** Older skin can become more sensitive over time, increasing the risk of allergic reactions. Expired makeup, with its potential breakdown products, can trigger these reactions, causing symptoms like redness, itching, and swelling.

4. **Dryness and Dehydration:** Expired makeup can also lead to dryness and dehydration. As we age, our skin naturally becomes drier. Using expired makeup can exacerbate this, leading to flaky, dehydrated skin.

5. **Accelerated Aging:** The harmful compounds that can form in expired makeup can accelerate the aging process. They can cause oxidative stress and damage the skin's collagen structure, leading to wrinkles and fine lines.

To avoid these issues, it's important to regularly check the expiration dates of your makeup products and replace them as necessary. Also, remember to store your makeup correctly (in a cool, dry place) to help extend its shelf life.