THE WASHINGTON POST – Before the pandemic began, dermatologist Adam Friedman routinely treated patients with pityriasis rosea, a temporary but often unbearably itchy skin rash that can last several months.
There are 170 cases of pityriasis rosea per 100,000 people each year, according to one study. It can affect people of all ages and races but predominantly afflicts those between the ages of 10 and 35, according to the American Academy of Dermatology.
But as the pandemic worsened, curiously, the condition “all but disappeared” from his practice, said Friedman, chair of dermatology at George Washington University School of Medicine and Health Sciences.
Then, once many people ditched masks and isolation, cases of pityriasis rosea came surging back.
The rash’s cause is unknown, but its pandemic-related behaviour “raises some intriguing possibilities” about its origins, Friedman said. An infectious agent, possibly spread through respiratory droplets or saliva, may be to blame.
“It’s a great example of how scientific clues unexpectedly come from real life,” he said.
When pityriasis rosea cases began vanishing, Friedman and other scientists analysed a database of three million patients in the United States with five skin conditions to understand why. They compared case numbers of pityriasis rosea with those of acne, atopic dermatitis, psoriasis and lichen planus and found a “statistically significant drop” in cases of pityriasis rosea that did not occur with the others.
The findings suggest that the cause of pityriasis rosea may be an infectious agent, possibly a virus. Some evidence already points to human herpesviruses six and seven, which have been found in patients’ skin lesions and saliva, “although the presence of these viruses doesn’t necessarily establish cause and effect”, Friedman said.
Before the pandemic, there was some speculation that the cause of pityriasis rosea might be a “reactivated” virus – a virus that lies dormant in the body and can re-emerge later. This bolstered that idea that human herpesviruses six and seven were to blame. Many people become infected at an early age with these two viruses – both can cause roseola, a childhood skin rash – which then stay in the body.
Pityriasis rosea’s pandemic-related behaviour, however, weakened that hypothesis, Friedman said, as stress often triggers herpes outbreaks, and the pandemic provoked considerable stress – but cases plummeted rather than increased. It’s more likely that cases are coming from new exposures, he said.
Several other studies have linked cases of pityriasis rosea or rashes similar to pityriasis rosea to coronavirus exposure or coronavirus vaccines, which can provoke rashes.
Some experts, however, doubt these rashes are pityriasis rosea.
“Many rashes can mimic pityriasis rosea, and it’s possible that the vaccine might cause a rash that looks like it,” said Shivani Patel, a Baltimore dermatologist.
Pityriasis rosea typically begins with one large round or oval scaly patch, known as the “herald” patch, often as big as an inch in size. This patch usually appears on the back or chest.
Within a week or two, a rash develops, often on the trunk, legs, arms, abdomen and groin area.
“While textbooks often describe the distribution of the rash as resembling a Christmas tree, atypical presentations often make diagnosis a challenge,” Friedman said.
Pityriasis rosea is not life-threatening, but it can be life-altering. It itches intolerably, said Alexander Arman, 64, of Rockville, who has been coping with it for more than two months, “especially at night”.
The rash is harmless, is not contagious by touch, disappears in a couple of months and usually never returns. Still, it is a source of considerable worry for patients who have no idea what it is or where it came from.
When patients show up in emergency rooms or urgent care centres, they often are told mistakenly they have ringworm, scabies or eczema, experts said.
“This causes them much distress,” said Misty Eleryan, a dermatologist in Santa Monica, California.
“I even had one patient who was convinced she had cutaneous lymphoma. Her primary care physician was going to refer her to a medical oncologist.”
Renee Fitzgerald, 60, first noticed her rash two months ago. “It looked like mosquito bites that started on my stomach”, then spread to other parts of her body, she said. She thought it may be ringworm or bedbugs.
“It can be scary” because it spreads so rapidly, Patel said. “There is one spot. Then they wake up one morning and it’s everywhere: chest, back, legs and arms.”
In some cases, the rash can leave significant staining on the skin, known as post-inflammatory pigment alteration, or hyperpigmentation. It results from inflammatory damage to the skin’s pigment, mostly on sun-exposed areas such as the face and arms, and especially affects people of colour.
“In some cases, it can be permanent,” Patel said, “but most of them resolve, although it takes a lot of time, six to nine months.”
Dermatologists have these suggestions to deal with the rash. If you are pregnant and develop the rash, though, the American Academy of Dermatology advises that you consult with your physician about treatment.
-A prescription topical steroid cream can help ease itchiness, and nonsteroidal anti-inflammatory creams can quench inflammation and clear the rash.
-Over-the-counter antihistamines can curb itching and redness. (The creams and antihistamines can be used at the same time, Friedman said).
– Oatmeal baths from commercial preparations can be soothing, but not hot showers – these release histamine, which increases itching.
-Moisturise, but avoid calamine lotion – it helps with the itch but dries out the skin. “Applying a moisturiser – especially one with colloidal oatmeal – to damp skin can help with inflammation and can soothe itch,” Friedman said, adding that consumers should look for eczema products, which contain colloidal oatmeal.
-Use mild soap and avoid harsh antibacterial soaps.
-Use sunscreen, or the sun can further discolour the affected areas.
“You want to arm the skin with all the things it needs to heal,” Friedman said. – Marlene Cimons
