Once in a while, we hear about a completely unexpected effect of a common medication. We really took notice when we got this report from a reader because we’d never heard of this reaction to the old-fashioned OTC medicine Campho-Phenique. Have you?
A Dab of Bite Remedy Seemed to Block Sunburn:
Q. A customer came in my store wearing shorts. Her legs were bright red from sunburn except some small spots that were white with no sunburn. I asked her about those white spots.
She said she had chigger bites and put Campho-Phenique on each one before she went out in the sun. Have you ever heard of Campho-Phenique to prevent sunburn?
What Is Campho-Phenique?
A. Campho-Phenique is an old-timey topical remedy that was introduced in 1884. At that time the camphor and phenol were in the form of a powder designed to treat wounds and other skin lesions.
Bayer’s Campho-Phenique Pain & Itch Relief still contains camphor and phenol along with inactive ingredients: colloidal silicon dioxide, eucalyptus oil, glycerin, light mineral oil. Bayer promotes this antiseptic liquid or gel for spot treatment of insect bites, cuts, scrapes, cold sores and sunburn. So far as we can tell, none of these ingredients are approved for preventing sunburn. Moreover, no one should apply Campho-Phenique over a large area of skin. Camphor could be toxic if a person absorbed a significant amount.
As we pored over the list of ingredients, we found that colloidal silicon dioxide is frequently included in sunscreen as an inactive ingredient. According to one manufacturer, some microspherical silicon dioxide products scatter UV light to make the active sunscreen ingredients more efficient. In summary, perhaps the colloidal silicon dioxide in the bite remedy was able to scatter UV light on those spots just enough to block sunburn there.