Allergic contact dermatitis to radiotherapy dye.

Area of Science:

• Dermatology
• Oncology
• Radiotherapy

Background:

• Radiotherapy port marking is crucial for accurate treatment delivery.
• Castellani's paint is a traditional topical agent used for marking skin sites.
• Resorcinol is a key component in Castellani's paint formulation.

Observation:

• A case of allergic contact dermatitis was observed.
• The dermatitis was linked to the use of Castellani's paint.
• The reaction occurred at the site marked for radiotherapy.

Findings:

• Resorcinol in Castellani's paint was identified as the causative agent.
• The patient presented with symptoms consistent with allergic contact dermatitis.
• Patch testing confirmed sensitivity to resorcinol.

Implications:

• Clinicians should be aware of potential resorcinol allergy in patients using Castellani's paint.
• Alternative marking methods or hypoallergenic paints may be considered for sensitive individuals.
• Further investigation into safer alternatives for radiotherapy port marking is warranted.