# What is New in Contact Allergy To Cosmetics for Physicians, Cosmetologists, and Cosmetic Users?

## TL;DR

This paper reviews recent developments in contact allergies caused by cosmetics, focusing on key allergens and new diagnostic and regulatory approaches.

## Contribution

The paper provides an updated overview of emerging cosmetic allergens and recent advancements in their diagnosis and regulation.

## Key findings

- Fragrances and hair dye chemicals like PPD remain major causes of contact allergy.
- Regulatory changes have reduced exposure to allergens like formaldehyde and isothiazolinones.
- New allergens are emerging in sunscreens, skin lighteners, and natural ingredients.

## Abstract

This paper aims to evaluate the burden of contact allergy caused by cosmetic products, identifying the key allergens involved and examining recent regulatory and diagnostic developments. The review addresses which substances commonly induce allergic contact dermatitis and how current trends and emerging allergens impact clinical practice.

Fragrances remain the most prevalent cosmetic allergens, with numerous compounds capable of triggering sensitization. Recent regulatory improvements in fragrance labeling are helping to reduce exposure to major allergens. Preservatives such as formaldehyde and isothiazolinones have historically caused widespread allergic reactions, but restrictions have lowered their incidence. Hair cosmetic allergens, especially para-phenylenediamine (PPD) and related chemicals, continue to cause significant allergic responses in consumers and professionals. Newly recognized allergens appear in sunscreens, skin lightening agents, and natural ingredients like propolis and carvone. The primary diagnostic methods include patch testing with baseline and specialized cosmetic allergen panels, photopatch testing for photoallergens, and repeated open application tests to support clinical evaluation.

Contact allergy due to cosmetics is a growing dermatological issue, primarily driven by fragrances and hair dye allergens, with emerging allergens contributing to the evolving landscape. Continued vigilance in diagnosis, improved regulatory measures, and increased reporting are essential to reduce allergy rates and enhance patient care. This review underlines the need for ongoing research and prevention strategies targeting novel cosmetic allergens.