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Sun Protection FAQ: Here's what you need to know

Spring has arrived - and so has the sun! This means that it’s time to protect your skin from the possible damage of sun radiation. For many people living with a chronic skin condition, it can be hard to find products that do not irritate the skin.

In general, your skin could potentially react to all of the ingredients in sun protection products. Many people think that the reactions are due to sun filters, however, most skin reactions are due to preservatives and fragrances in the sun cream rather than the sun filter itself.

It can be hard navigating the jungle of misleading information about sun protection. The following article answers some of the most frequent questions.

How do sun filters actually work?

Sunscreens are classified on the basis of their mode of UV protection:

  • Physical blockers, sometimes referred as ‘inorganic’ or ‘mineral based’, block the sun’s rays by making a thin ‘film’ on the skin reflecting the rays. In order to be efficacious and not creating a white cover on the skin, these molecules are nowadays very small (typically in the size range around 100 nm or below). Therefore it is a myth that these filters make a white cover on your skin. If you experience a white and greasy product like this, it might be because of the other ingredients in the products making the product unable to absorb properly. Physical blockers include titanium oxide and zinc oxide.
  • Chemical absorbers penetrate the skin and absorb the sun’s ray preventing them from penetrating the skin. In general, these chemical filters are the cause of many allergic reactions to sunscreens. Chemical absorbers include octocrylene and benzophenones.

What is SPF?

SPF stands for ‘Sun Protection Factor’. It is a theoretical factor referring to prevention of sunburn under laboratory conditions. In general, the SPF is a way to quantify how much a sunscreen is protecting you compared to not using any sunscreen. If your skin allows 10 minutes in the sun without burning, a SPF15 allows 15 times longer stay, meaning 150 minutes. This is only an estimate and depends on the intensity of sun radiation, skin type and amount of used sunscreen.

What should I be aware of when living with sensitive skin?

For people living with sensitive skin such as eczema, it is recommended to use sunscreens with the physical blockers zinc oxide and titanium oxide. These ingredients are not associated with irritation or sensitization, because they do not interact with the deeper layers of the skin.  

Allergic reactions to sunscreens can be classified in two different ways:

  • ‘Allergic contact dermatitis’ which is your skin reacting to the exposure of any of the ingredients. This could be chemical sun filters, perfumes etc.
  • ‘Photoallergic contact dermatitis’ happens when the chemicals filters enter the skin and are exposed to the rays altering the molecular structures. This lead to the formation of a contact allergen which irritates the skin.

Currently, most allergic reactions to chemical filters are related to ‘benzophenones’ (benzophenone-3 / oxybenzone), the ‘PABA derivatives’ (ethylhexyl dimethyl PABA) and dibenzoymethane (butyl methoxydibenzoymethane).

Is it possible to completely block the sun?

No. When using sunscreen you block out most of the sun radiation. A SPF15 sunscreen filters 93 % of the UV rays, whilst SPF30 and SPF60 sunscreen filter out 96.7% and 98.3% respectively. This doesn’t mean that SPF60 is only marginally better than SPF30. On the contrary; because SPF60 transmits 1.7% compared to 3.3% by SPF30, it means SPF60 protects you twice as effectively as SPF30.

It is complicated! But to keep it simple: All dermatologists recommend to use at least SPF15, preferably SPF30.

Do I still get the required amount of Vitamin D if using sun creams?

It is a myth that you don’t get the required vitamin D if using sunscreens. If this was the case, you would have to apply excessive amounts of sunscreen. So don’t worry! Your body will still produce the healthy Vitamin D it needs.

How often should I use it?

Sunscreen should be applied 15 minutes prior to sun exposure. This allows the cream to absorb or create the protective film. Sunscreen should be reapplied after swimming or vigorous activity even though the product is labelled ‘waterproof’.

How much sunscreen should I use?

More than you think! Sunscreen needs to be applied liberally. Choosing a sunscreen spray might be tempting, especially if you have kids. In this case, you need to pay extra attention, since it can be hard to add enough of the product resulting in a discontinuous film and thereby reduced sun protection. If you want to be sure to apply enough, it is recommended to use creams or lotions. Pay specific attention to the back of the neck, the ears and scalp areas with thin hair.

What is the difference between UVA and UVB?

The radiation from the sun reaching the earth’s surface is divided into UVA and UVB depending on their wavelength. In general, it is the UVB which mainly causes sunburn with maximal redness and pain peaking 24 hours after sun exposure. The UVA radiation is mainly responsible for skin cancer and ageing. Sun filters are targeting either UVA, UVB and some products are categorised “broad spectrum” sunscreens, meaning that they provide protection through the entire spectrum of UV radiation.

Important: To find out how your skin reacts to the sunscreen, apply a small amount of the product to your inner forearm and do not wash the area for 24 hours. Be aware of any signs of an allergic reaction including redness, any form of breakouts, pain etc.

All Sunscreens available on HelloSkin were screened by our medical team to find the most suitable sunscreens for people living with sensitive skin.

See our sunscreen collection here

References:

Emedicine - medscape, April 2018
Photodermatol Photoimmunol Photomed. 2014 Apr.
Am J Clin Dermatol. 2002;3(3):185-91
British National Formulary 68th Edition

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