Keto Diet: Itchy Skin Side Effect Explained

The ketogenic diet is a popular eating plan that involves eating a low-carb, high-fat diet. While it can lead to weight loss, it can also cause some unwanted side effects, including brain fog, fatigue, and electrolyte imbalance. One of the most common side effects is an itchy rash. This rash, known as keto rash or prurigo pigmentosa, is an inflammatory skin condition that typically occurs on the torso, back, and neck. It is characterised by itchy, raised skin lesions that can be red, brown, or light pink. The exact cause of keto rash is unknown, but it is believed to be linked to ketosis and the production of ketones, specifically acetone, which can irritate the skin. The rash usually goes away within a few weeks of stopping ketosis, but it can leave lasting discolouration on the skin.

Keto rash is a rare inflammatory skin condition

Keto rash, also known as prurigo pigmentosa, is an inflammatory skin condition that can develop as a result of the ketogenic diet. It is a rare condition, and researchers are still unsure of its exact cause. However, it is believed that a change in the gut microbiome from a sudden change in eating habits, such as a drastic reduction in carbohydrate intake, can contribute to the development of keto rash.

Keto rash typically presents as itchy, raised skin lesions that are red, brown, or light pink in colour. These lesions often form a symmetrical pattern on each side of the body and are most commonly found on the torso, back, chest, neck, shoulders, and underarms. In rare cases, the rash may also appear on the face and extremities.

The rash usually develops in four stages, starting with early lesions that resemble light pink scratch marks. This is followed by fully developed lesions, which are more aggressive and can include liquid-filled or pus-filled cysts. As the rash starts to recede, the lesions become crusted, scaly, and darker in colour. In the final stage, the skin is left with a web-like pattern of dark spots, which may remain long after the rash has healed.

While keto rash is not life-threatening, it can be uncomfortable and unsightly. The rash typically resolves within a few weeks of stopping ketosis and increasing carbohydrate intake. However, it is important to note that the rash may leave lasting discolouration on the skin.

There are several treatments and lifestyle measures that can help alleviate the symptoms of keto rash. These include wearing loose-fitting clothing, avoiding irritants such as wool or strong detergents, and moisturising the affected area. In some cases, antibiotics such as minocycline or tetracycline may be prescribed to treat the symptoms.

The medical term for keto rash is prurigo pigmentosa

Prurigo pigmentosa has been described in people of all ages, sexes, and ethnicities, but it is more common among Asians, particularly young women. Women are twice as likely to be affected as men. It has been increasingly associated with ketotic states associated with diabetes, fasting, and post-bariatric surgery.

The exact role of the exclusion of carbohydrates and ketosis in the development of prurigo pigmentosa has not yet been fully understood. Several other mechanisms have been proposed, including friction with clothes or a contact allergy to trichlorphenol, chromium in acupuncture needles, chrome in detergent, and nickel.

The clinical features of prurigo pigmentosa are:

• A pruritic (itchy) rash, which may recur
• Inflamed, red raised spots (papules) that merge to form a reticulate (network-like) pattern
• Symmetrical distribution on the trunk, most often affecting the upper back, sacrum (natal cleft), abdomen, and chest
• Rare involvement of the face or limbs
• Sparing of mucous membranes, hair, and nails
• Reticulated hyperpigmented patches following the resolution of the inflammatory phase of the rash

Prurigo pigmentosa responds well to tetracycline and has an excellent prognosis. Dapsone and tetracycline antibiotics are effective in treating prurigo pigmentosa during the inflammatory phase of the disease. These treatments are thought to work by interfering with the movement and function of neutrophils.

For keto rashes that occur due to ketosis, eating more carbohydrates will usually resolve the rash, as this moves the body out of ketosis. In people with diabetes, administering insulin can reduce keto rashes.

The rash is characterised by itchy, raised skin lesions

The rash, known as "keto rash" or prurigo pigmentosa, is characterised by itchy, raised skin lesions. The skin lesions can be red, brown, or light pink in colour, depending on the stage of the rash. The rash typically affects the torso, back, chest, neck, shoulders, and underarms, but in rare cases, it can also appear on the face and extremities.

The rash usually forms a symmetrical pattern on each side of the body, with a web-like or network-like appearance. It can worsen with exposure to heat, sweat, friction, and other potential skin irritants. The rash is typically more aggressive in the second stage, with red skin lesions (called papules) that may include liquid-filled cysts or, more rarely, pus-filled cysts.

In the third stage, as the rash starts to resolve, the papules become crusted, scaly, and darker in colour. The final stage, or late lesions, is characterised by a web-like pattern of dark spots, larger than freckles, called reticulated hyperpigmentation. This pigmentation may remain long after the rash has healed.

The rash can be red, brown or light pink

The keto rash, or prurigo pigmentosa, is an inflammatory skin condition that can be identified by its red, brown or light pink rash. It is an uncommon but irritating side effect of starting a ketogenic diet.

Prurigo pigmentosa is also called Nagashima disease, after the Japanese town where it was first reported in 1971. It is more common in female teenagers and young adults, and most of the in-depth research on the subject has involved young Japanese women. The rash typically affects the torso, back, neck, chest, shoulders, and underarms, and can be symmetrical on both sides of the body.

The rash has four stages. In the first stage, light pink raised skin lesions called "urticarial papuloplaques" appear on the skin. These can look like scratch marks, but shouldn't be neglected as the rash can advance to the next stages. The second stage is when the rash is fully developed, with red skin lesions (called papules) that are more aggressive and sometimes include liquid-filled cysts. In the third stage, the lesions start to resolve, and the papules become crusty, scaly, and darker. In the final stage, the skin is left with a web-like appearance of dark spots larger than freckles, called "reticulated hyperpigmentation". This can remain long after the rash is healed.

The exact cause of the rash is unknown, but there is a promising hypothesis that it is linked to the production of a ketone body called acetone. When entering ketosis, the body produces more acetone than usual, and this is excreted through the breath and sweat. When acetone is released through sweat in high concentrations, it can irritate the skin and cause dermatitis-like symptoms.

There are several treatments for keto rash. Firstly, it may go away on its own within a few weeks, especially if you are new to keto and your body is still adjusting. If not, you can try increasing your carbohydrate intake to get out of ketosis and see if the rash starts to heal. You can also try eliminating allergens from your diet, as a drastic diet change can increase the risk of provoking food allergies. Another option is to supplement your diet with vitamins, minerals, and omega-3s, as nutrient deficiencies can lead to rash-like symptoms.

The rash is preventable and treatable

The keto rash, or prurigo pigmentosa, is preventable and treatable. The rash is an inflammatory skin condition that results in itchy, raised red spots across the torso, back, neck, shoulders, and abdomen. It is more common in young Asian women, but it can happen to anyone, especially those on the keto diet.

Prevention methods

If you are starting the keto diet and want to prevent the keto rash, you can try the following:

• Transition to keto slowly by gradually lowering your carbohydrate intake over time, rather than suddenly.
• Pay attention to minor rash symptoms and increase your carb intake as soon as you see any signs of a keto rash.
• Supplement your diet with vitamins and minerals to avoid deficiencies, especially during the first few weeks of the keto diet.

Treatment methods

If you are experiencing the keto rash, there are several ways to treat it:

• Reintroduce carbohydrates: Eating more carbs and exiting ketosis will usually resolve the rash within a day or two. You can still get most of the benefits of a keto diet by doing a more liberal low-carb diet (50-100 grams of carbs per day) with intermittent fasting.
• Correct nutrient deficiencies: Nutrient deficiencies may play a role in inflammatory skin conditions, so eating a variety of colourful fruits and vegetables can help ensure you're getting all the necessary vitamins and minerals.
• Eliminate food allergens: Many common keto-friendly foods, such as dairy, fish, shellfish, and tree nuts, are also common food allergens. Eliminating these foods from your diet may help reduce rash symptoms.
• Incorporate anti-inflammatory supplements: Probiotics, prebiotics, vitamin D, and fish oil supplements have all been used in clinical studies to help improve symptoms of dermatitis.
• Take care of your skin: Use lukewarm water for bathing and showering, clean with gentle soaps and cleansers, moisturize dry skin, and protect your skin when exposed to elements like hot sun or cold wind.
• Talk to your doctor about medication: If home treatments don't work, your doctor may prescribe antibiotics such as minocycline or doxycycline, or dapsone.

Frequently asked questions