Diabetic medications such as Wegovy (semaglutide) and Mounjaro (tirzepatide) have become increasingly popular ever since their weight loss potential has been promoted.
However, concerns have started to be raised about the link between these weight loss drugs (called GLP-1 inhibitors) and a type of irreversible vision loss called NAION or non-arteritic anterior ischaemic optic neuropathy.
[https://www.reviewofoptometry.com/news/article/risk-of-naion-higher-in-patients-on-glp1-drugs-for-diabetes-or-weight-loss]
[Hathaway JT, Shah MP, Hathaway DB et al. Risk of Nonarteritic Anterior Ischemic Optic Neuropathy in Patients Prescribed Semaglutide. JAMA Ophthalmol 2024 Jul 3: e242296. Doi: 10.1001/jamaophthalmol.2024.2296]
However, as these are just observational studies more work needs to be done to assess causality.
It was not long ago that another popular weight loss diet, the ketogenic diet was all the rage. However, dermatologists started seeing odd rashes in people pursuing ketogenic diets, something we called the ‘keto rash’ and a case of keto rash (or prurigo pigmentosa) is described in the July issue of Clinical & Experimental Dermatology.
[Ze-Hu Liu. Unexpected journey with the ketogenic diet: a patient’s experience with prurigo pigmentosa. Clinical and Experimental Dermatology Advance Article, 18-19 July 2024.]
What does the ‘keto rash’ look like?
It typically starts with itchy red spots on the trunk and neck area. These can occur within a month of starting the diet. It might then turn into little blisters. It then resolves to leave pigmented or brown areas. If the diet is stopped, the itchy spots tends to resolve within 2-3 weeks but the brown areas persist for some time.
Why does it happen?
A ketogenic diet involves extremely low levels of carbohydrate intake, a moderate protein intake and a high fat intake. This induces a level of ketosis in the body. These ketones accumulate around blood vessels in the skin, causing an inflammatory reaction which causes the itching.
The high levels of ketones can be detected in the urine which can help in making the diagnosis.
What is the treatment?
Antibiotics can be given that reduce the inflammatory response but essentially, resumption of a balanced diet is the key.
It just shows you that more often than not, there is no ‘free ticket’ in life and that if you want to lose weight, doing it the hard way, ie eating less and moving more, might actually be the safest way to do it.
Kind regards,
Sandy
Consultant Dermatologist.
