Introduction

Irritant contact dermatitis (ICD) is a major cause of complaints by consumers and dermatology patients. The causes for ICD are numerous and the inflammatory pathways activated are dependent on the irritant. The initiation phase of the cutaneous irritation is variable and the closely related to the physicochemical properties of the irritant. It is at the later stages of the inflammatory process, when chemical mediators are involved, that the different inflammatory pathways converge toward a common mechanism. Irritation or inflammation, no matter what causes it or how it happens, impairs the skin’s immune and healing response. And although your skin may not show it or doesn’t react in an irritated fashion, if you apply irritants to your skin the damage is still taking place and is ongoing, so it adds up over time.

Anti-irritant systems may thus be relatively effective against specific types of irritants if their effect usually occurs early in the inflammation reaction, or effective against other types of irritants if they effect occur during the later phases of inflammation. Many anti-irritant systems that have been identified, are based on new technologies, or simply are based on a better understanding of the interaction between the irritant and the skin and knowledge on how to modulate the irritant’s effect. Some of the best-known anti-irritants have been described for surfactants, free radical species originators, and sensory irritants, as well for the inflammatory phase common irritants. Fundamental research on chemical mediators involved in the inflammatory reaction and on neurotransmitters responsible for sensory irritation can still contribute a great deal to this field, and it is expected that many new molecules will be identified in the future to help reduce product-related skin irritation. Generally, surfactants, fragrances and preservatives are the primary sources of skin irritations.

Most moisturizers include fragrances, which give the product a fresh, pleasing odor and cover up the smell of other ingredients. Fragrances in skin-care products are the most likely cause of skin irritations or contact allergies.

Any product that includes water and oil must contain one or more preservatives to help prevent bacterial contamination after the product is opened. Most products contain multiple preservatives. These ingredients can sometimes cause skin allergies or reactions.

Harsher cleansers contain anionic surfactants which are potent irritants.

Major Anti-Irritants

1. Allantoin
2. Cyclomethicone
3. Dipotassium glycyrrhizate
4. counter-irritants
   • menthol
   • peppermint
   • camphor
   • mint

Appendix: Irritating Ingredients

• Preservatives
  • Parabens (methyl-, butyl-, ethyl-, and propyl-)
  • Formaldehyde and Formaldehyde-releasing preservatives
  • benzoic acid
• Fragrance
  • Phthalates
  • methylene chloride
  • toluene
  • methyl ethyl ketone
  • methyl isobutyl ketone
  • ethyl alcohol
  • benzyl chloride
• Surfactants in cleansers (Anionic Surfactants)
  • fatty acids (carboxylate)
  • sulfonate and sulfate ions – “sodium-based
• Emulsifier
  • diethanolamine (DEA) and DEA related derivatives
    • oleamide DEA, lauramide DEA, cocamide DEA
• Thickening Agents (gel formulation)
  • diethanolamine (DEA)
  • Solanum tuberosum (potato) starch

• Allantoin