For many people, the fragrances and chemicals in certain shampoo may cause an allergic reaction, with symptoms that range from sneezing to contact dermatitis (dry, itchy, and irritated scalp).
This article will explore the specific causes of an allergic reaction to shampoo, the signs and symptoms, and how to treat it.
What is an Allergic Reaction?
When an allergen (an outside element) like pollen or dust enters the body, it causes the immune system to react. This sets off a chain reaction by producing immunoglobulin E (IgE) antibodies that are specific to an allergen.
These antibodies act as “cleaners” and eliminate the allergens from your system, resulting in the release of a histamine, a chemical created in the body that’s released by white blood cells into the bloodstream when the immune system thinks it’s under attack. An allergic reaction is triggered when the histamine is released.
Signs
Signs of an allergic reaction can be mild, moderate, or severe:
Mild reactions can affect certain areas of your body, like your skin (with a rash or hives), your eyes (which can become red and watery), or your nose (which may run). These symptoms are common for an allergy like dust mites or hay fever. Mild reactions stay local and don’t spread to other parts of the body. Moderate symptoms tend to spread to other parts of the body. They include hives, itchiness, swelling, and even difficulty breathing. Severe reactions, which are rare but life-threatening, are known as anaphylaxis, which can start with extreme itchy eyes and face and then progress to throat swelling. This can cause problems with swallowing and breathing. Other symptoms include abdominal pain and cramps, vomiting, diarrhea, hives, mental confusion, dizziness, and a big drop in blood pressure.
Shampoo and Allergies
Although shampoo doesn’t have long contact with the scalp and surrounding skin areas because of rinsing, a shampoo allergy is one of the main causes of scalp dermatitis.
It may be difficult to diagnose since it involves many areas where the shampoo comes into contact, including the:
ScalpEarsBehind the neckHandsUpper torso
Switching shampoos may not relieve or improve symptoms because many products contain the same ingredients. To determine a shampoo allergy, a patch test with personal items may help pinpoint the allergen. However, there is a high rate of false-positive patch test results.
Symptoms
Shampoo allergy symptoms may depend on the chemical(s) listed in the ingredients. The most common symptoms, which can appear between 24 to 48 hours, include:
Red skin on the neck, face, upper torso, and handsScaly patches on the scalp, face, ears, and back of the handsOozing blistersIntense burning and itchingSwelling of the face and eyesHivesSun sensitivity
If you experience any of these symptoms, contact your healthcare provider and ask for a referral to see an allergist, a doctor specializing in allergies and asthma.
What to Do
If any symptoms appear within the 24 to 48-hour time frame, stop using the shampoo. Do not wait for the symptoms to go away. Instead, call your healthcare provider, especially if symptoms last longer than one to two weeks.
Most likely, your healthcare provider will refer you to an allergist who will determine the allergen with a skin patch test. Bring the shampoo with you to help the specialist locate the primary chemical that may be causing the allergy.
If the patch test can’t be fulfilled, a blood panel may be taken. Note the blood test isn’t as sensitive as a patch test, but it will determine the number of antibodies produced by your immune system.
Prevention
The best way to prevent the allergic reaction is to stop using the shampoo. Ask your healthcare provider or allergist for recommendations.
Research alternatives that will help keep both your scalp and hair clean and won’t dry out your skin. Your hair stylist may also be able to recommend a milder product.
Summary
For many of us, our hair is a source of pride. We take great measures to keep it clean, soft, healthy, and shiny. But when our shampoo is the cause of an allergic reaction—whether mild or severe—it’s time to consider retiring it.
If allergic symptoms persist (burning, itching, red skin, hives, etc.), don’t wait to see if they disappear on their own. Make an appointment with your healthcare provider or allergist to determine the allergen causing the discomfort.

SneezingRed, itchy, eyesHivesShortness of breath or wheezingSwelling
