3.3. Adverse Reactions to Chemicals and Products
💡 First Principle: An adverse reaction means the client's body is responding negatively to a product or treatment. Your job is not to diagnose the cause — it is to stop the service, remove the product, document what happened, and refer the client to a medical professional if warranted.
Adverse reactions can range from mild redness to severe allergic responses. The esthetician cannot always predict them in advance — even clients who have used a product before can develop a reaction. This is why patch testing is a critical preventive tool, and why recognizing and responding to reactions promptly is a core professional skill.
Types of reactions:
| Reaction Type | Signs | Immediate Action |
|---|---|---|
| Irritant contact dermatitis | Redness, burning, stinging at application site | Remove product immediately with cool water |
| Allergic contact dermatitis | Itching, hives, swelling (may spread beyond application site) | Remove product, stop service, monitor, refer if worsening |
| Anaphylaxis (severe allergic reaction) | Difficulty breathing, throat swelling, dizziness | Call 911 immediately — this is a medical emergency |
Patch testing: Before applying a new product — especially chemical exfoliants, peels, or products with active ingredients — a patch test identifies sensitivity before a full-face application. Apply a small amount to the inner wrist or behind the ear, wait 24–48 hours, and check for any reaction before proceeding.
When a reaction occurs during a service:
- Stop the service immediately
- Remove the product with cool water (do not apply additional products)
- Do not continue the service
- Document the product used, the client's response, and the time
- If the reaction is severe or worsening, advise the client to seek medical care
⚠️ Exam Trap: The exam may present a scenario where a client's skin is reacting mildly and the esthetician continues the service while monitoring the reaction. This is incorrect — the service must stop when a reaction is identified. Continuing risks worsening the reaction.
Reflection Question: A client who has received facials before suddenly develops hives 10 minutes into a facial using the same products as always. What does this tell you about adverse reactions, and what should you do?
