Allergic reactions to SPF creams are skin eruptions that appear after applying a sun protection product and show as redness, swelling and itching.
Allergic reactions to SPF cream are skin eruptions that appear after applying a sun protection product and show as redness, swelling, itching and, sometimes, small fluid-filled blisters. These reactions are rare, appear almost exclusively with creams containing chemical filters, and in most cases resolve by changing the product. Worth remembering: an allergic reaction is not a reason to give up sun protection, but to choose a formula your skin tolerates better.
As it has become understood that excessive exposure to ultraviolet radiation is responsible for an increased risk of skin cancer and for the premature ageing of the skin, using sunscreen has become a matter of routine.
Choosing the sunscreen that suits your skin is not always straightforward, because several things have to be taken into account: the intensity of the sunlight, how long you are out in the sun, your skin type (phototype), any conditions that may be made worse by sun exposure, allergies to the substances in sunscreens, and so on.
A suitable sunscreen has, in the main, to meet a few conditions: it should have a broad spectrum of photoprotection, that is, it should block both kinds of radiation responsible for actinic damage to the skin, UVA and UVB; it should have a protection factor (SPF) of at least 30 for effective protection; it should suit your daily activity — for example, if you are going to swim you will use a water-resistant sunscreen; and it should be well tolerated by your skin, so that it does not leave an unpleasant feeling after application.
Kinds of SPF cream
According to how they work, sunscreens are divided into those that provide chemical photoprotection and those that provide mechanical photoprotection.
1. Sunscreens that provide chemical photoprotection have the property of absorbing UV radiation, which, on contact with the molecules in the cream, is transformed into radiation harmless to the skin. At the same time, sunscreens providing chemical photoprotection are absorbed into the skin.
Among the most widely used substances found in sunscreens that provide chemical photoprotection against UVA are: benzophenone, oxybenzone, dioxybenzone and avobenzone.
The substances most frequently used for chemical photoprotection against UVB are: OMC (octyl methoxycinnamate), ethylhexyl p-methoxycinnamate, salicylates, OCS (octyl salicylate), homomethyl salicylate, triethanolamine, PABA (para-aminobenzoic acid), padimate A and O, glyceryl aminobenzoate, octyl dimethyl PABA, octocrylene and derivatives of cinnamic acid.
2. Sunscreens that provide mechanical photoprotection do not absorb ultraviolet radiation as the previous kind does, but protect the skin by reflecting it. These kinds of cream are not absorbed by the skin, and the risk of allergic reactions is low, because they are non-allergenic and non-irritant. The substances that do this are:
– zinc oxide: alongside photoprotection against UVA it adds anti-microbial and anti-irritant properties.
– titanium dioxide, a substance in the form of mineral particles, non-irritant and non-comedogenic, with a great capacity to reflect ultraviolet radiation.
Most often the sunscreens on sale are a combination of the two mechanisms of photoprotection, chemical and mechanical.
How does an allergic reaction to sunscreen show itself?
The widespread use of sunscreens has led to the appearance of a distinct category of allergic reactions, those appearing after using a sunscreen. Even so, this category of allergic reaction is rare and appears only with creams providing chemical photoprotection. No intolerance reactions have been seen with creams providing strictly mechanical photoprotection.
Allergic reactions to sunscreens show as a skin eruption in which the skin is red and swollen, with a local itching sensation. Small, extremely itchy fluid-filled blisters often appear on the surface of the affected skin. Usually only the area where the sunscreen was applied is affected, but in some cases the eruption may spread beyond it.
Kinds of reaction to sunscreen
Allergic reactions to sunscreens are divided into:
Contact dermatitis to sunscreens
This is a true allergic reaction to one of the ingredients of the cream. It usually appears a few hours to a day or two after exposure and involves the immune system.
Photodermatitis (photoallergic contact dermatitis)
This appears only through the combination of applying the cream to the skin and exposure to ultraviolet radiation. Without sun exposure, this kind of reaction is not set off.
Irritation (irritant contact dermatitis)
This is not an allergy as such. It appears quickly, with a burning, stinging or smarting sensation, with no immunological mechanism. It is the commonest complaint about sunscreens.
To diagnose contact dermatitis to sunscreens, other diseases with similar skin manifestations have to be ruled out: lupus erythematosus, porphyria, polymorphous light eruption and so on.
An allergy to sunscreen is confirmed by standard allergy testing (patch test); where the result is negative, allergy testing combined with exposure to ultraviolet radiation (photopatch test) must be carried out.
Which ingredients in UV protection creams most often cause allergies?
The substances in sunscreens most frequently blamed for allergies are:
– Para-aminobenzoic acid (PABA) and its derivatives: these were very frequently used in these creams and, because they often stained clothing and caused skin allergies, they were gradually removed. Very few creams contain these substances today, and creams free of PABA and its derivatives are promoted instead.
– Benzophenones: substances frequently used in making sunscreens, but which can give rise to unwanted allergic reactions. Other names for benzophenones are: oxybenzone, methanone, mexenone, benzophenone 3, 4 and 8.
– Derivatives of cinnamic acid have been blamed for allergies after applying sunscreens.
– Salicylates: benzyl salicylate and other products with the word “salicylate” in their name can be a source of allergic reactions.
– Dibenzoylmethane and octocrylene, two more substances introduced more recently into sunscreens, have been behind allergic reactions.
Mineral (physical) filters such as zinc oxide and titanium dioxide very rarely cause reactions, because they are not absorbed by the skin and are considered non-allergenic and non-irritant.
Chemical filters versus mineral (physical) filters
Sunscreens fall into two categories, according to how they work:
- Chemical filters: they absorb ultraviolet radiation and turn it into heat. This is where most allergic reactions appear.
- Mineral (physical) filters: they protect the skin by reflecting ultraviolet radiation rather than absorbing it. Zinc oxide adds anti-microbial and anti-irritant properties to its photoprotection, and titanium dioxide is a non-irritant, non-comedogenic mineral particle with great reflective power. The risk of allergic reactions is low, which is why these formulas are the first choice for sensitive or allergy-prone skin.
Most often, the creams on sale combine the two mechanisms, chemical and mechanical.
How is the diagnosis made?
The diagnosis is mainly clinical and is made by the dermatologist, according to the appearance and the location of the eruption and to the history of using the product. To identify the substance at fault precisely, the doctor may recommend:
- the patch test, for allergic contact dermatitis;
- the photo-patch test, for photoallergic reactions, in which the tested area is exposed to ultraviolet radiation under controlled conditions.
What to do if you have an allergic reaction to an SPF cream
If a reaction occurs, the first steps are:
- stop using the suspected product immediately;
- wash the area gently with water, without harsh soaps;
- apply a cold compress to calm the itching and the redness;
- see a dermatologist for assessment and to identify the ingredient responsible.
Depending on the severity, the doctor may recommend a topical corticosteroid cream or an antihistamine to ease the itching. If the eruption spreads rapidly, is intense, or is accompanied by difficulty breathing or swelling of the face, seek emergency medical help.
How to choose a sunscreen suited to sensitive skin
Choosing the right sunscreen takes several things into account: the intensity of the sunlight, how long you are exposed, your skin type (phototype), any conditions made worse by the sun, and known allergies to ingredients. In general, a suitable sunscreen should meet the following conditions:
- a broad spectrum of photoprotection, blocking UVA as well as UVB;
- a protection factor (SPF) of at least 30 for effective protection;
- compatibility with your daily activity (for example, a water-resistant formula if you swim);
- good tolerance by the skin, with no unpleasant sensations after application.
For sensitive or allergy-prone skin, choose a mineral formula (with zinc oxide or titanium dioxide), fragrance-free, labelled hypoallergenic.
How to prevent allergic reactions
The simplest precaution is to test any new product on a small area of skin for 1 to 2 days before applying it to the whole face or body. Read the list of ingredients, avoid known allergens, and prefer mineral, fragrance-free formulas if your skin is reactive.
The people at risk of developing allergic reactions to sunscreens are: people with conditions made worse by exposure to ultraviolet light, people with atopic dermatitis, people who have applied sunscreen to previously irritated skin, and people who work outdoors, through chronic exposure to ultraviolet light.
For people allergic to ordinary sunscreens, it is advisable to use sunscreens that block ultraviolet radiation strictly mechanically (creams based on zinc oxide and titanium dioxide particles).
Sun protection remains essential
Although allergic reactions do exist, they are rare and do not justify giving up sun protection. Excessive exposure to ultraviolet radiation increases the risk of skin cancer and accelerates the ageing of the skin. The right answer is not to give up sunscreen but to replace it with a better-tolerated formula, preferably a mineral one.
When to see a dermatologist
A specialist consultation is advisable if:
- the eruption does not improve after stopping the product;
- the reaction is severe or spreads;
- reactions recur with several products;
- you want to identify exactly which ingredient causes your allergy;
- you need help choosing a product suited to your skin type.
Frequently asked questions about allergies to SPF creams
Can I be allergic to all sunscreens?
Usually not. Reactions appear to particular chemical filters, or to fragrances and preservatives, not to every product. Mineral creams are generally well tolerated even by sensitive skin.
Can a mineral sunscreen cause allergies?
Very rarely. Zinc oxide and titanium dioxide are non-allergenic and non-irritant, and are recommended for people with reactive skin.
How long does an allergic reaction to sunscreen last?
Once the product has been stopped and the allergen avoided, the eruption usually improves within a few days to a week or two. If it persists, see a dermatologist.
What is the difference between an irritation and an allergy?
An irritation appears quickly, with a burning or smarting sensation, and does not involve the immune system. An allergy usually appears a few hours or days after exposure and is an immunological reaction to a particular ingredient.
Can I use sunscreen if my skin is sensitive?
Yes. Choose a mineral, fragrance-free formula and test it first on a small area of skin.