From greasy street food to cheap hotel soap, travel shakes up all the good habits that keep your skin happy and healthy. In fact, the flight alone is the biggest skin stressor, causing the body to lose up to 1.5 liters of water on barely a three-hour flight. Factor in long-haul journeys combined with varying weather and environmental changes, and your skin is exposed to mega dehydration before you’ve even checked into your first hotel.

If you notice annoying breakouts and flaky dry skin that only seem to appear when you travel, you’ll want to pinpoint the cause. Here are the main reasons why your complexion freaks out and how to best prepare and care for it while traveling.

1. You bought skincare products you don’t usually use.

Whether you plan to rely on the hotel creams or you’ve bought whatever travel-sized cleansers you found at the drugstore, this is not the time to forgo your regular skincare routine. On average, it takes about 28 days for skin cells to turn over, which means you need to wait at least one month before you’ll see results. This is especially risky for those with sensitive/irritable skin or who are acne-prone, notes Dr. Tsippora Shainhouse, a board-certified dermatologist at SkinSafe Dermatology.

For the best results, grab reusable travel-sized containers and fill them with your normal products. These BPA-free silicone bottles are a great sustainable option for your core products. You can also utilize an old contact lens case to store expensive serums and eye creams.

2. You’re not getting enough rest.

Even if you prioritize sleep, uncomfortable beds, time changes, and noisy nightlife can still keep you awake. For long-haul travelers, supplementing with melatonin — the hormone that regulates the sleep-wake cycle — can help cure jet-lag while noise-canceling headphones such as those from Sleep Authorities, will become crucial for quality sleep on that plane, hostel, or overnight bus.

It’s not just to avoid baggy under-eyes, either. “Lack of sleep can trigger inflammation (hello, pimples!), water loss (dry, flaky, tight, irritated skin), and puffiness,” explains Shainhouse. Sleep allows your skin cells to recharge, repair, and regenerate so you wake up feeling and looking rested.

3. You’re not prepared for the cabin climate.

Every time you board a plane, you’re stepping into stale, recycled air with only 10 to 15 percent humidity. And when there is lack of moisture, the air will draw water from any source it can — including your skin. “I recommend skipping the heavy makeup look and instead going for a fresh-faced, light appearance,” says Catie Wiggy, vice president of marketing and product innovation at MyChelle Dermaceuticals, “and a hydrating cream with hyaluronic acid to lock in moisture.” Also key in your in-flight skincare routine is SPF — windows on planes not only don’t block ultraviolet rays but also leave you exposed to more UVA light as you climb 20,000 feet closer to the sun.

4. You traveled to a place with a different climate or season.

Our oil glands respond to hot and cold climates by going into overdrive, so jumping geographic zones quickly doesn’t give our skin time to acclimate. If you have oily skin, arm yourself with a mattifying lotion like the Murad Oil and Pore Control Mattifier and its clarifying body spray to help fight body breakouts. People with dry skin and those in windy environments will want to protect the moisture in their skin with extra serums and a lip balm with solar protection. Try the Jack Black Intense Therapy Lip Balm with SPF 25 for any destination.

5. You’re gorging on the sweet stuff.

Even if your mantra is that vacation calories don’t count, it’s important to understand how your skin’s health depends on the balance of your digestive system — including sugar. Studies show that your body has a buffer to handle short-term overeating of up to about a week. Anything more than that can affect your insulin production and lead to weight gain, insulin resistance, and skin changes. “High glycemic index [sugary] foods are associated with acne development,” explains Shainhouse, noting to splurge when you want but to try out a moderate diet plan on extended vacations if you’re acne-prone.

6. You’re not wearing enough SPF.

“It’s a myth that sun clears up acne,” says Shainhouse, noting that sun exposure puts you at risk for painful sunburn and UV-associated inflammation which can actually cause breakouts. Even if you apply sunscreen before heading on a day tour, you’ll want to prioritize reapplying throughout the day — which is just as important. The good news is sunscreen can be properly applied over makeup so you can take it on the go. Catie Wiggy’s favorite: the MyCHELLE Dermaceuticals Sun Shield Liquid, a 100 percent mineral sunscreen for maximum UVA/UVB broad-spectrum protection.

7. You’re in a city with high air pollution.

No matter if you travel to a big city or a rural town, almost 80 percent of the world’s population breathes polluted air, according to NASA. While there are adverse effects of pollution greater than bad skin, traveling to a city with higher pollution rates is a skin concern for most people. Not only is your skin’s exposure to air pollutants associated with dermatitis, eczema, and psoriasis, but small airborne pollutants can get stuck in your pores, causing acne-like breakouts. This is often called chemical- or pollution-induced acne.

Smog, especially the ground-level ozone it causes, depletes natural antioxidants on the skin, like vitamins C and E. To combat this, look for anti-pollution skincare products formulated with antioxidants. Try the Sunday Riley C.E.O. Vitamin C Rich Hydration Cream, an antioxidant-infused moisturizer with lime pearl extract and exopolysaccharides, which fight micro pollution found in smog. You can also add leave-on AHA or BHA exfoliants to your travel routine if you’re headed to a big city. This extra step helps dislodge the pollutants that get trapped in your pores.

8. The water quality is different from what you’re used to.

Hard water has a high accumulation of dissolved minerals, mainly calcium and magnesium, and it’s a nuisance in most major cities. While it has no known adverse health effect, hard water can’t properly dissolve soaps, leaving leftover residue on your skin that draws out your natural oils and leaves your skin feeling dry and irritated. A water softener — currently the best solution for a purer rinse — is not feasible for travelers. If you’re dealing with tight-feeling skin from hard water while traveling, Westlake Dermatology recommends opting for a gentler face wash than your normal go-to for less irritation. If acne is your problem, consider using only distilled water for your facial cleanse.

9. You’re stressed out.

Physiological and physical stress can create undesirable changes in our skin. So between pre-travel jitters and navigating foreign territory, it’s easy to send your cortisol (stress) levels into high gear. Check in with your anxiety levels both pre- and mid-trip so you can fly with confidence, then embrace the right travel mentality so you can enjoy the experience and keep acne at bay.