A Summer Tale of the Mystery Rash


A few weeks ago my oldest noticed a red rash and a few odd “spots” on his forearm. The spots itched and looked like bug bites so I applied anti-histamine ointment and told him to ignore the area. If you scratch you’ll only make it worse! Days went by and new spots manifested daily.  I was boggled.  Was this hives?  Did we have a bug problem in the house? Did he get into poison ivy?

Two weeks into the saga his skin condition worsened and he  grew more and more uncomfortable. Sites of the rash that were once small, separate entities, coalesced into large, rough, red regions fully covering his arms and legs. When it began to spread to his upper chest and face I became concerned and was clear out of ideas – what on earth was causing this?

I sent some pictures to my Pediatrician and she agreed we should come in for an evaluation. It wasn’t until my son was sitting on the exam table with three hovering, perplexed adults – myself with two pediatricians, that one of us took a step back and noticed a key feature previously overlooked. The rash was only on the sun exposed areas of his body! It was just a theory, but my pediatrician wondered whether or not our sunscreen was to blame.

Well sure, why not? We apply sunscreen daily, occasionally multiple times during the day. I’d used a bunch of different brands on him over the last several months, and had never had an issue before, but what if he’d slowly developed a sensitivity? A sunscreen allergy wasn’t completely out of the realm of possibilities, and I was a bit embarrassed I hadn’t considered it myself.

The incidence of sunscreen allergy is difficult to assess, but it’s common enough that in talking with my medical peers most see a handful of cases per year.  Thankfully, most allergic reactions are mild, causing a simple skin rash.  If the sunscreen itself causes the rash, the reaction is considered a contact dermatitis.  If the reaction occurs upon activation of the sunscreen by sunlight, the reaction is called a photodermatitis or photoallergy. Either way, the result is an uncomfortable, often itchy situation.

To be completely frank, trying to figure out what component of a sunscreen your child is allergic to is difficult, and oftentimes trial and error.   The ingredient list on the back of sunscreen bottle is impressively long with chemical ingredients, fragrances, emollients/carriers, stabilizers and more. There is so much in there a kid could be sensitive to!

Certainly, the easiest scenario is a sensitivity to an inactive ingredient, such as added fragrance or an emollient such as coconut oil. If this is the case, the solution is simple. There are many sunscreens on the market that are fragrance and additive free.


More complicated is a sensitivity to an active ingredient.  Active ingredients in sunscreen, such as PABA and benzophenones, work by absorbing the sun’s UV rays.  These chemicals are generally the culprit in cases of sunscreen dermatitis.  Thankfully, chemical sunscreens are not the only option in protecting your one’s skin from the sun. For sensitive kids, one’s best bet is switching to a physical sunscreen.

Ah, the 80's. When zinc oxide sunscreens as a fashion statement had their hey day,
Ah, the 80’s. When zinc oxide sunscreens as a fashion statement had their hey day,

Physical sunscreens are hypoallergenic and very well tolerated – even by those with the most sensitive of skin.  They work by reflecting UVA and UVB rays away from from the body.  Because of this capacity to reflect, and essentially “block” the sun’s rays, these types of sunscreens are also known as “sunblocks.”

In the past, physical sunscreens could be spotted on one’s skin by their characteristic opacity – the type of sunscreen that never, fully, blends in. This was a big reason why chemical sunscreens came into vogue, they were much more subtle to wear.  Thankfully, newer formulations of physical sunscreens have tinier particles which allow for translucent application.  Interested in testing one out?  Look for sunscreens that list “zinc oxide” or “titanium dioxide” as the only active ingredient.

Sunscreen allergies can be insanely frustrating, especially if you have active, outdoorsy kids. For our family, we’re letting my son’s rash calm down for a bit and then we plan to switch to a zinc oxide based product. If he continues to rash, despite switching sunscreens, the next step is a referral to an allergist to confirm his diagnosis and to consider allergy testing.  Let’s hope there’s an easy fix so my kiddo can get back to outdoor activities fast!  Anyone else out there have a kid who may be sensitive to sunscreen?

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A Summer Tale of the Mystery Rash by Sarah Kiser, CPNP-PC is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

About sarahkiser

Pediatric nurse practitioner, writer, mother of two.

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