Why Does the Keto Diet Cause a Skin Rash?

Keto rash, or prurigo pigmentosa, is a rare inflammatory skin problem. Also called Nagashima disease, the keto rash causes an itchy rash with vesicles (fluid-filled blisters). It often appears on your neck and trunk. The blisters change and crust into darker-pigmented spots that form a netlike pattern.

The keto rash is often linked to the ketogenic (keto) diet or health conditions that produce ketosis. In this state, your body uses stored fat rather than glucose for energy. The ketogenic diet is a low-carbohydrate, high-fat eating plan. It is most often recommended to treat people with epilepsy that is hard to control.

Treatments for the keto rash include home cures like increasing carbohydrate intake and making up for vitamin deficiencies. Antibiotics and other drugs are often useful when these treatments don't work.

This article explains all you need to know about the keto rash, its causes, treatments, and ways to prevent it.

What Does the Keto Rash Look Like?

The appearance of a keto rash can vary based on your skin tone and texture. Most case reports are in people in Asia and the Middle East, with some reports in White or Hispanic people. Descriptions of the rash in people of darker skin tones are lacking.

The condition includes the following characteristics:

Inflamed, itchy, red papules (small, well-defined skin bumps) or vesicles

Symmetrical distribution of spots on your trunk and neck

Occasional appearance of spots on your face, scalp, and suprapubic region (lower abdomen and groin)

Rare involvement of mucous membranes, hair, and nails

Formation of a netlike pattern of dark spots as the inflammatory phase of the rash ends and the bumps scale and crust

While a keto rash can affect anyone, it is most common among people of Asian descent. It affects women twice as often as men, though it may be due to a higher prevalence of dieting behaviors among women than men.

A keto rash typically occurs 31 days after starting a keto diet. For most people, the rash subsides about 18 days after ending the keto diet.

A Note on Gender and Sex Terminology

Verywell Health acknowledges that sex and gender are related concepts, but they are not the same. To reflect our sources accurately, this article uses terms like “female,” “male,” “woman,” and “man” as the sources use them.

What Causes a Keto Rash?

The exact cause of a keto rash is not known. The rash is named as a result of its link to the ketogenic diet.

A ketogenic diet involves limiting protein and carbohydrates, so most of your energy is produced from fat. The lack of carbohydrates in the diet triggers a state of ketosis, in which your body derives energy from the breakdown of fat. Ketosis can also be triggered by fasting, insulin-dependent diabetes, or bariatric surgery.

There is growing evidence that the connection between the keto rash and ketogenesis may involve the gut microbiome (the microorganisms in your digestive tract). An imbalance in the gut microbiome triggered by ketogenesis may impact a person's immune response, leading to a keto rash.

In addition to ketosis, the following potential triggers for the condition have been identified:

Sweating

Friction from clothing

Chromium in acupuncture needles

Atopic dermatitis (eczema)

Diabetes

Anorexia nervosa (eating disorder)

Rapid weight loss

Pregnancy

Sjögren’s syndrome (an autoimmune disease that affects moisture-producing glands and tissues)

Helicobacter pylori (H. pylori) infection (bacterial infection)

How to Treat the Keto Rash

The best way to treat a keto rash varies by individual. Contact a healthcare provider regarding the onset of a keto rash or any rash that persists and worsens. Some of the following strategies may provide relief or even resolve symptoms.

Reintroduce Carbohydrates

You may be able to treat a keto rash by reintroducing carbohydrates without returning to average carbohydrate intake levels. This may help you maintain the benefits of a keto diet without the side effect of a keto rash.

Research indicates that modifying carbohydrate intake with guidance from a registered dietitian nutritionist (RDN) trained in ketogenic therapies can help achieve lower prescribed carbohydrate levels. There is evidence that maintaining these defined carbohydrate levels can reduce the keto rash without sacrificing ketogenesis.

Correct Nutrient Deficiencies

Removing entire food groups from your diet can lead to nutrient deficiencies. Research indicates that certain nutrient deficiencies manifest as skin disorders.

Consuming a low-carbohydrate diet like the keto diet increases the risk of nutritional deficiencies due to a lack of nutrients from vegetables, fruits, whole grains, and legumes. As a result, low-carb diets are often insufficient in the following nutrients:

Thiamin

Folate

Vitamin A

Vitamin E

Vitamin B6

Calcium

Magnesium

Iron

Potassium

Eliminate Food Allergens

Following a keto diet involves increasing your intake of fats to meet the high-fat requirement. Unfortunately, keto-friendly foods such as eggs, dairy, fish, and nuts, which meet this criteria, are among the most common food allergens.

If you have a specific food allergy, consuming the allergen can trigger or worsen a rash. It is important to have the allergy diagnosed and then avoid the specific food allergen.

According to the American College of Allergy, Asthma, and Immunology, the following eight types of foods account for 90% of all adverse food reactions:

Eggs

Milk and dairy

Peanuts

Tree nuts

Fish

Shellfish

Wheat

Soy

Sesame

Depending on your level of sensitivity, a food allergy can trigger life-threatening effects. Get immediate medical help if you have any of the following signs of a food allergy:

Vomiting and/or stomach cramps

Hives

Shortness of breath

Wheezing

Repetitive cough

Shock or circulatory collapse (interruption of blood circulation)

Tight, hoarse throat; trouble swallowing

Swollen tongue, affecting your ability to breathe or talk

Weak pulse

Pale or blue skin color

Dizziness or feeling faint

Anaphylaxis (a life-threatening reaction that can impair breathing and send your body into shock; possibly with multiple allergic symptoms)

Incorporate Anti-Inflammatory Supplements

There is some evidence that certain nutritional supplements may help reduce inflammation in the treatment of atopic dermatitis (eczema). While the research is inconclusive and warrants further investigation, symptom improvement of skin disorders has been linked to the following nutrients:

Evening primrose oil

Fish oil

Vitamin D

Vitamin E

Prebiotics and probiotics

Take Care of Your Skin

To care for skin affected by a keto rash, follow these general guidelines to protect the affected area and relieve symptoms of inflammation and itching:

Avoid scrubbing your skin when bathing or scratching to relieve itching.

Use fragrance-free and dye-free gentle cleansers.

Discontinue the use of cosmetic lotions or ointments.

When bathing, use warm (not hot) water and avoid scrubbing with a washcloth or loofah.

Pat dry, don't rub your skin after bathing.

Allow the affected area to remain exposed to the air whenever possible.

Add colloidal oatmeal to a lukewarm bath to relieve itching.

Try the following topical treatments: moisturizers, calamine lotion, hydrocortisone cream (1%)

Discuss Medications With a Healthcare Provider

Depending on your symptoms and the extent of your rash, your healthcare provider may recommend medications to treat your keto rash.

Research indicates that oral and/or topical prescription medications can resolve a keto rash within 18 days when combined with discontinuation of the ketogenic diet. A commonly used treatment is oral doxycycline, ranging from 100 to 200 milligrams daily for two weeks to two months.

Your healthcare provider can determine the best medication for your condition, which may include the following:

Oral minocycline

Topical steroids

Topical antibiotics

Oral antihistamines

Oral prednisolone

Topical antifungals

How to Prevent a Keto Rash

Any drastic dietary change can trigger side effects. Reducing your carbohydrate intake to a very low level very quickly is likely to increase your risk of developing a keto rash.

While there is no definitive way to prevent a keto rash since its cause is unknown, you may be able to reduce your risk of having the condition by taking the following measures:

Consult a healthcare provider before starting a ketogenic diet to develop a plan of action that involves a safe, slow transition into a new eating plan.

Don't ignore any rash symptoms, no matter how minor. Try increasing your carbohydrate intake at the first sign of a rash to prevent symptoms from becoming worse. If the ketogenic diet has been prescribed for epilepsy, discuss the rash and any recommended dietary changes to relieve it with a healthcare provider.

Consult a healthcare provider to discuss the types of vitamins and minerals needed to balance a keto diet to avoid deficiencies.

Stay hydrated by drinking as much water as possible and limiting caffeinated beverages.

Summary

The keto rash is a blister-like rash often linked to the keto diet or other causes of ketosis. Ketosis is the state in which your body uses fat rather than glucose for fuel.

The keto diet is mainly used to treat drug-resistant epilepsy. However, it has also been used for weight loss and diabetes management.

Your risk of having a keto rash or other symptoms may increase as your body adjusts to a keto diet. While it may have healthful uses, the keto diet is a very strict eating plan. It is best started with the oversight of a healthcare provider.

Contact your healthcare provider if you are following a keto diet and notice any signs of a skin rash or other irritation. While a rash can be linked to the keto diet, it can also be a sign of health conditions that require treatment.

Read the original article on Verywell Health.