What are the optimal guidelines for sunscreen use in Australasia (Australia and New Zealand)?

From the Guidelines

For optimal sun protection in Australasia, apply a broad-spectrum, water-resistant sunscreen with SPF 50+ every two hours when outdoors, using approximately one teaspoon for each limb, front, back, and face/neck (about 35ml for a full-body application). Apply 20 minutes before sun exposure and reapply after swimming or excessive sweating. Choose sunscreens containing ingredients like zinc oxide, titanium dioxide, avobenzone, or octocrylene for comprehensive UVA and UVB protection. In Australasia's intense UV environment, combine sunscreen with other protective measures:

• wear sun-protective clothing
• a broad-brimmed hat
• and sunglasses, and seek shade between 10 AM and 4 PM when UV radiation is strongest. Children under six months should be kept out of direct sunlight rather than using sunscreen. This comprehensive approach is essential in Australasia, which experiences some of the world's highest UV levels due to its proximity to the equator, relatively clear atmosphere, and the ozone layer depletion over Antarctica that affects southern regions, particularly during summer months 1.

Key considerations for sunscreen selection include:

• Broad-spectrum protection against UV-A and UV-B rays
• SPF of at least 15, but preferably 50+ for optimal protection
• Water-resing formula for individuals who will be sweating or swimming
• Non-derogatory ingredients for sensitive skin types
• Avoiding sunscreens with para-aminobenzoic acid (PABA) for sensitive individuals
• Being mindful of the expiration date, as some sunscreen ingredients may degrade over time 1.

It is also crucial to follow proper application guidelines, including applying sunscreen approximately 30 minutes before sun exposure and reapplying after swimming or strenuous exercise 1. Additionally, public health recommendations emphasize the importance of combining sunscreen use with other protective measures, such as seeking shade, wearing protective clothing, and avoiding peak sun hours 1.

Ultimately, the goal is to minimize exposure to the sun during peak hours and to use sunscreen as a complementary measure to other forms of sun protection, rather than relying solely on sunscreen for protection 1.

From the Research

Optimal Sunscreen Use in Australasia

• The use of broad-spectrum SPF 30+ sunscreens is recommended for individuals living in tropical or subtropical climates, such as Australasia, to achieve adequate protection from the sun 2.
• Broad-spectrum sunscreens provide better protection from solar ultraviolet-simulated radiation and natural sunlight-induced immunosuppression in human beings 3.
• Sunscreen application method can affect SPF measurement, and many individuals use less than half the amount of sunscreen recommended 2.
• Topical sunscreens decrease the quantity of ultraviolet (UV) light from the sun reaching the skin by either blocking or scattering it and help protect the skin from dyspigmentation, photoaging, DNA damage, and photocarcinogenesis 4.

Adverse Reactions to Sunscreens

• Adverse reactions to sunscreens are uncommon in relation to their widespread use, and can be related to both active and inactive ingredients in sunscreen products 5.
• The main cutaneous adverse reaction patterns to sunscreens can be divided into allergic and irritant contact dermatitis, phototoxic and photoallergic contact dermatitis, contact urticaria, and, in solitary cases, anaphylactic reactions 5.
• Nearly all adverse effects due to active sunscreen ingredients reported to date are related to the organic UV filters, which are sometimes also referred to as "chemical UV filters" 5.
• Inorganic UV filters, such as zinc oxide and titanium dioxide, possess minimal skin-irritating properties or sensitization potential 5, 6.

Recommendations for Sunscreen Use

• Individuals should be encouraged to use only broad-spectrum SPF 30+ sunscreens to achieve adequate protection from the sun 2.
• Sunscreen products providing efficient photoprotection throughout the entire UV spectrum are necessary to prevent UV-impaired response 3.
• Dermatologists should be aware of reactions to active ultraviolet filters and perform patch and photopatch testing to common UV filters when clinically indicated 6.