Contact dermatitis: facts and controversies.

Area of Science:

• Dermatology
• Allergology
• Toxicology

Background:

• Contact dermatitis (CD) has been studied for over a century, with Josef Jadassohn pioneering patch testing.
• Despite extensive research, numerous controversies and unanswered questions persist in the diagnosis and understanding of CD.

Observation:

• The review focuses on specific areas of disagreement within CD research.
• Key controversies include identifying the true sensitizer in balsam of Peru and the role of low-balsam diets.
• Discrepancies in formaldehyde sensitization prevalence between the US and Europe, and the relationship between formaldehyde releasers and formaldehyde allergy are examined.

Findings:

• The exact sensitizer in balsam of Peru and the efficacy of dietary interventions remain debated.
• The allergenic potential of benzalkonium chloride, known for its irritant properties, is questioned.
• The prevalence and causative agents of cocamidopropyl betaine (CABP) allergy, lanolin allergy, and systemic nickel-induced CD are subjects of ongoing investigation and controversy.
• Cross-reactivity and concomitant sensitization between nickel and cobalt are also discussed.

Implications:

• Resolving these controversies is crucial for accurate diagnosis and effective treatment of contact dermatitis.
• Clarifying these issues will aid practicing dermatologists in managing patient care and advising on allergen avoidance.
• Further research is needed to address the persistent enigmas in contact dermatitis, such as the lanolin paradox.