Harmful misuse of white vinegar in a wrong combination

Dear Editors,

We read with great interest an article entitled, ‘Unusual burn injury due to application of white vinegar and aspirin mixture’, by Irkoren and Sivrioglu 1. They have reported second‐degree burn injury on both the legs of a 60‐year‐old male patient following application of a mixture consisting of white vinegar (acetic acid) and aspirin (acetylsalicylic acid) prepared by adding white vinegar to five aspirin tablets, mixed together in a container. The mixture was applied to treat knee pain in both the legs.

Household vinegar contains 4–5% acetic acid and is used as a condiment, salad dressing, preservative in cooking, mild disinfectant, medicinal tonic and ‘softener’ or ‘deodorant’. Dilute acetic acid at a concentration of 1–5% has been used successfully by many workers in the treatment of skin and soft tissue infections, and burn infections caused by Pseudomonas aeruginosa, including multidrug‐resistant strains 2, 3, 4. In our previous studies also, we have used 3% acetic acid (5% in one case) to treat pseudomonal wound infections and could successfully treat the same without any adverse reactions 5, 6, 7. Although not bactericidal, acetic acid merely creates an acidic environment unfavourable for the growth of P. aeruginosa 8.

Although this weak acid at a concentration of 0·25% has been reported to kill fibroblasts in an in vitro model in one study 9, and has been shown to slow down the wound epithelialisation and to limit polymorphonuclear neutrophil function in another study 10, to the best of our knowledge it has never been reported to cause burn injury. In our previous study also, we did not notice skin burn or any other adverse reaction, even when applied to open wounds 5, 6, 7.

Although direct contact with acids is known to cause chemical burns of varying severities depending on the type of acid and the length of exposure, it is not always true with weak acids such as acetic acid, citric acid and boric acid in dilute concentrations. In this case, the skin burn is due to combination therapy of acetic acid and acetylsalicylic acid (aspirin) – a mixture of two different acids, the concentration of which is not exactly known.

This is a very interesting observation showing that an application of a combination of acetic acid and acetylsalicylic acid can cause a split‐thickness chemical burn. We congratulate the authors for bringing out this potential side effect of the combination therapy to the medical world and showing that the practice of using white vinegar in a wrong combination and for a wrong purpose (for relieving pain) is an incorrect and unsafe procedure.

Although acetic acid in a combination with acetylsalicylic acid is toxic to skin, it is our personal experience that acetic acid alone is non‐toxic to skin as well as to open wound and shares the advantages of many topical agents; hence, the use of acetic acid as a topical agent should not be ignored when there is a shortage of therapeutic options, especially in skin and soft tissue including burn infections caused by multiple antibiotic‐resistant P. aeruginosa.

Basavraj S Nagoba, PhD1, Namdev M Suryawanshi, MD1 & Sohan P Selkar, MPhT2
1Department of Microbiology, Maharashtra Institute of Medical Sciences & Research, Latur, India
dr_bsnagoba@yahoo.com
2MIP College of Physiotherapy, Latur, India