What You Need To Know About Paradoxical Adipose Hyperplasia

Cryolipolysis is generally considered a safe and effective form of body contouring, but adverse effects (however rare) are possible. Here’s what you need to know about PAH.
Written by Meg Storm
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What You Need To Know About Paradoxical Adipose HyperplasiaAlexander Krivitskiy/Unsplash

Linda Evangelista made headlines on social media this week when she candidly opened up about her experience with paradoxical adipose hyperplasia (PAH), which she says she developed after a series of cryolipolysis treatments five years ago. In an emotional Instagram post, the supermodel alleges the CoolSculpting® procedures “increased, not decreased” her fat cells and left her “permanently deformed even after two painful, unsuccessful, corrective surgeries.”

Linda Evangelista's Instagram post about her experience with PAH. (@lindaevangelista/ Instagram)

By sharing her story, Evangelista (who filed a lawsuit against the device’s manufacturer, Zeltiq Aesthetics, which is a subsidiary of Allergan) has paved the way for a renewed conversation around one of the lesser known adverse effects of the popular fat-freezing procedure. So, what is paradoxical adipose hyperplasia and how common is it? Here, a top dermatologist and plastic surgeon break down everything you need to know about PAH — including how to treat it.

What Is Paradoxical Adipose Hyperplasia?

To understand paradoxical adipose hyperplasia (PAH), it’s first important to understand cryolipolysis. Also known as ‘fat freezing’ or by its brand name, CoolSculpting®, the non-invasive body contouring procedure is a controlled cooling technique that works by freezing fat cells at negative 11 degrees Celsius to permanently destroy them. “Cryolipolysis uses cooling to damage and destroy subcutaneous fat cells without damaging the skin to reduce the amount of fat in the treated area,” says Paul Jarrod Frank, MD, a board certified dermatologist in New York City.

Most patients experience a 20 to 25 percent reduction of fat in the treatment area, and CoolSculpting® is approved by the United States Food and Drug Administration (FDA) to address visible fat bulges on the back, buttocks, thighs, upper arms, flanks, and abdomen and under the chin and jawline. According to the CoolSculpting® website, post-treatment side effects include “temporary redness, swelling, blanching, bruising, firmness, tingling, stinging, tenderness, cramping, aching, itching, or skin sensitivity, and sensation of fullness in the back of the throat after submental or submandibular area treatment.”

The site also notes that “rare side effects” may occur: “CoolSculpting® and CoolSculpting® Elite may cause a visible enlargement in the treated area, which may develop [two] to [five] months after treatment and requires surgical intervention for correction.” The paradoxical adipose hyperplasia Evangelista describes was first reported in 2014. “It is a rare, previously unreported adverse effect of cryolipolysis,” Dr. Frank notes.

PAH refers to hardened areas of localized fat that develop after cryolipolysis. “PAH is the unintentional growth of adipose, or fat, after cryolipolysis,” explains Melissa Doft, MD, a double board certified plastic and reconstructive surgeon in NYC. “Patients complain of a thick layer of hard fat in a similar shape to the applicator used for CoolSculpting®, and it has been described as looking like a stick of butter.”

Studies show that less than one percent of patients (about 0.05 percent to 0.39 percent) experience the condition after cryolipolysis, though more recent data indicates the figure may be as high as 0.72 percent. “It is unclear why some patients have the growth of fat cells instead of reduction, but what is known is that the incidence is higher than was previously expected,” Dr. Doft says. “Researchers estimated that it affects one in 138 patients who undergo cryolipolysis and is more common in male patients.”

As such, providers increasingly believe PAH does not get enough attention. “This complication is more common than we think, along the spectrum of mild to severe,” Dr. Frank shares. In her IG post, Evangelista laments that she was “not made aware” of the risk prior to undergoing treatment.

While it is not life threatening, PAH can be physically and emotionally distressing — and it will not go away without treatment. “I do not have a CoolSculpting® machine, but I have seen several complications unfortunately,” Dr. Doft shares. “It is devastating to the patients.”

What Causes Paradoxical Adipose Hyperplasia?

The tricky thing about paradoxical adipose hyperplasia? We don’t really know exactly what causes it. “We assume the cooling effect has some sort of stimulatory stem cell activation which causes multiplication of fat cells,” Dr. Frank explains, adding that it is “typically a localized phenomenon.” That means most patients who experience PAH do so in the area where the cryolipolysis applicator was placed, and it can happen anywhere on the body.

Additionally, it can happen to anyone. “There is no data on why someone is more susceptible than others,” Dr. Frank says. “That makes it such a problem because it's unpredictable.” One potential factor? “People who get too many repetitive treatments in the same area may be more inclined to have PAH,” he adds.

For example, there could be situations in which a patient is misdiagnosed after CoolSculpting®. “The most common cause is when a patient says they have a CoolSculpting® cycle, and they start noticing growth in the area,” Dr. Frank explains. Rather than recognize the growth as PAH, an untrained provider may blame it on weight gain and have the patient undergo another session. “It usually happens when you have too many CoolSculpting® treatments in a short period of time to the same area,” he says.

How to Treat Paradoxical Adipose Hyperplasia

The most important thing to know about treating paradoxical adipose hyperplasia is that additional cryolipolysis treatments are not the answer. Instead, liposuction or, in more severe cases, abdominoplasty (read: tummy tuck) are the most effective ways to improve or completely correct PAH. Be aware that multiple surgeries may be needed.

The coldness of cryolipolysis creates inflammation that destroys fat cells, but it can also cause panniculitis, or the inflammation of fat. “That causes a rebound and exacerbation of scar tissue that comes from the inflammation,” Dr. Frank explains. As such, “it is necessary for patients to wait six to nine months after the [cryolipolysis] procedure to confirm that the inflammation and growth has plateaued,” Dr. Doft adds. During that time, “people who are experiencing the active stage of growth soon after CoolSculpting® treatment require systemic steroids,” Dr. Frank notes.

At Dr. Frank’s practice, vaser liposuction is the “gold standard” of treating fat adipose hyperplasia. “Most patients get enormous improvement after one treatment,” he explains, but many patients “will require two rounds of surgical intervention to really reduce the irregularities.”

Dr. Doft agrees that liposuction often “works well to remove the excess fat tissue,” though it is not always enough. “Some patients not only have excess fat but also significant scar tissue and will need an abdominoplasty to correct the problem,” she says.

The Takeaway

Even non-invasive treatments that are generally considered safe and effective, like CoolSculpting®, can have negative outcomes that require costly revision. “[PAH] is a more common than discussed complication, particularly in the hands of unlicensed professionals and med spas,” Dr. Frank cautions. While all aesthetic procedures carry the possibility of side effects and complications, visiting a board certified provider who specializes in the treatment you are interested in can help mitigate risk and ensure you are in qualified hands should something go wrong.

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  1. H. Ray Jalian, MD, Mathew M. Avram, MD, JD, Lilit Garibyan, MD, PhD, Martin C. Mihm, MD, R. Rox Anderson, MD. (2014). Paradoxical Adipose Hyperplasia After Cryolipolysis. JAMA Dermatology, 150(3): 317–319. doi: 10.1001/jamadermatol.2013.8071
  2. Michael E. Kelly, Jose Rodríguez-Feliz, Carolina Torres, Emma Kelly. (2018). Treatment of Paradoxical Adipose Hyperplasia following Cryolipolysis. Plastic and Reconstructive Surgery, 142(1): 17e. doi: 10.1097/PRS.0000000000004523
MEG STORMis the editorial & content director at AEDIT.

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