Allergic contact dermatitis to pure henna

Area of Science:

• Dermatology
• Natural Products Chemistry

Background:

• Henna (Lawsonia inermis) is a natural brown dye traditionally used for cosmetic and cultural purposes.
• Its active component, lawsone (2-hydroxy-1,4-naphthoquinone), is generally considered to have low allergenic potential.
• Allergic reactions are often attributed to chemical additives like diaminotoluenes and diaminobenzenes in commercial henna mixtures.

Observation:

• A case of allergic contact dermatitis is reported.
• The reaction was specifically linked to the use of pure henna.
• This pure henna was also being used for the relief of rheumatic pain.

Findings:

• Pure henna, devoid of common chemical adulterants, can elicit allergic contact dermatitis.
• This challenges the prevailing assumption that reactions are solely due to additives.
• The study documents a specific instance of hypersensitivity to natural henna.

Implications:

• Clinicians should consider pure henna as a potential allergen in contact dermatitis cases.
• Further research into the allergenic properties of pure henna and its constituents is warranted.
• Patients using henna for cosmetic or therapeutic purposes should be aware of potential allergic risks.