A young Saudi man, 22, who went on a zero-carb diet developed a rare skin disease because of low carbohydrate levels in his body, health experts at University Hospital Sharjah (UHS) said on Saturday.

He was treated by prescribing a dietary plan that also included carbs.

Low or zero-carb diets are popular diets — with the ketogenic diet being a current trend — and proponents say that forcing the body to switch to proteins and fat instead of carbs for energy causes rapid weight loss. However, there can be health implications of such diets, UHS said on Saturday.

UHS experts determined a restrictive carbohydrate had caused health problems for the Saudi man as well as a Jordanian woman aged 23.

In the case of the Saudi patient, the restrictive diet plan led him to develop prurigo pigmentosa, a rare inflammatory skin disease.

Dr Fatma Mostafa, consultant dermatology at UHS, said: “When the young Saudi national visited us, he had an itchy rash all over the right side of the torso, with a lesser extension on the left side. The rash appeared one week before the visit and had increased progressively with severe itching. The patient had not worn any new clothes, changed the detergents used for his laundry, any new soap or shampoo, and or worn any metal accessories.”
She added: “During his history-taking, he confirmed that he was on a carbohydrate-free diet two weeks back, which was one of key factors that led to the prurigo pigmentosa.”
Although it is uncomfortable, the rash is not life-threatening or dangerous. It looks similar to eczema and dermatitis.

“While there are several topical and systemic treatments available to treat prurigo pigmentosa, we treated the young man with a simplistic yet effective dietary plan that also included carbohydrates. There was dramatic improvement after removing the precipitating factor, which suggested early stage prurigo pigmentosa due to a carbohydrate-free diet.”

Similar to the Saudi man, the Jordanian woman also suffered from the same condition after prolonged Ramadan fasting and a recurrent carbohydrate-free diet. She also experienced similar symptoms and was offered treatment with oral tetracycline along with dietary modifications, which now incorporates carbohydrates.

“The Jordanian patient also had the same condition, however, she was treated with two options as she suffered from it frequently. Prurigo pigmentosa usually forms a symmetrical pattern on each side of the body, in a net-like distribution. Like most rashes, it can worsen if the patient exercises strenuously or exposes the rash to heat, moisture and friction,” said Dr Fatma.

Adding carbohydrates back into the diet can cut down yeast and bacteria, Dr Fatma pointed out, which explains why eating carbs helps the rash disappear.