Skin can be a fickle thing. One day it’s clean and clear and ready for a close-up, and the next thing you know it’s a war zone among your pores.

When serums, ointments and pills just aren’t cutting it, it may be time to investigate the real reason behind your skin’s tumultuous roller coaster ride.

We chatted with three ladies who discovered the root of their skin’s unhappiness stemmed from unlikely sources, and how something as little (or big) as dropping ingredients from their diet made all the difference.

Nicola Kavanagh-Trinidade

Irritant: Sugar

The problem: “I had bad acne but only around my chin area — this is the area associated with hormones and your reproductive system.”

The diagnosis: “I actually quit sugar as part of a detox I was doing to cut out refined foods and sugar to improve digestive issues I was having. My skin clearing up as a result of the diet was a complete surprise. We forget that until 100 years ago almost nobody ate sugar on a regular basis, now it’s added to everything and it’s very unhealthy for our bodies.”

The change: “Within a matter of weeks my skin went from having inflamed red pimples to being perfectly clear. Going sugar-free was more effective than any skin treatment, antibiotic ointment or facial!”

Moderation is key: “My skin will show me immediately when I’ve been eating sugar. I can get away with perhaps one sweet treat a week — like a gluten-free brownie — but any more than that and the pimples come back immediately.”

Jessie Grobmyer

Irritant: Dairy

The problem: “I was experiencing significant skin inflammation in the form of bumps and breakouts — specifically on the face around the chin and jawline.”

The diagnosis: “As the frustration grew, I did some research and started experimenting with elimination and reintroduction of certain things in my diet and quickly figured out that dairy was definitely a big part of the problem.”

The change: “After about two weeks to a month, I noticed my skin was clear again and I didn’t have to stress about embarrassing bumps and finding harsh chemical treatments to try to fight it.”

How she’s adapted: “I do avoid milk, cream-based foods, dairy cheeses, yogurt, ice cream, etc. because the tradeoff is not worth it to me. I’ve switched to using almond or coconut milk, yogurts made with coconut milk, and goat cheese if any at all. I really don’t miss cheese or any of those things because I know the price!”

Amy Bell

Irritant: Phenoxyethanol

The problem: "I had horrible acne and figured I just had bad skin. A dermatologist told me to take antibiotics every time I had a breakout, so I tried to treat it myself instead. I spent so much money on products, but it turns out they were all causing allergic reactions."

The diagnosis: "I’ve been dying my hair for years, but in May 2016 I broke out with a severe rash that looked like a chemical burn. A friend referred me to River City Dermatology for a full skin allergy test. I was allergic to a laundry list of things, including a common preservative called phenoxyethanol. I bet if you looked at all the products in your bathroom right now 99 percent of them would have it."

The change: "It took a few months, but my skin cleared up dramatically. The first change I noticed was in how my skin felt. It always felt like I had tiny bumps under the surface. A few weeks after getting rid of phenoxyethanol, my skin felt completely smooth."

What works for her: "VMV Hypoallergenics is a safe line for me to use. Makeup has been a little more difficult. B. Barnett worked with me to find a good CC cream to replace my foundation, and I’ve also found makeup through Beauty Counter."