Why do I get a rash from body lotion?

Is it irritation or an allergy?

Irritant contact dermatitis happens when a substance damages the skin's outer protective layer. Burning, pain, dryness and rough patches can occur. A strong irritant can cause symptoms quickly, while milder irritation can build with repeated use. This is the more common type and does not require an allergy. Eczema that weakens the skin barrier increases your risk.345

Allergic contact dermatitis involves your immune system reacting to an ingredient. It often causes intense itching, swelling or blisters, with the rash appearing 24 to 48 hours after contact. You can develop an allergy after tolerating a lotion for years, so an old favourite is not automatically innocent.4

Contact dermatitis can look red on lighter skin and dark brown, purple or grey on darker skin. Raised, itchy welts appearing within minutes to an hour can instead be contact urticaria, a type of hives that usually settles within 24 hours. Timing helps describe the reaction, but cannot identify the ingredient by itself.36

Which ingredients cause problems?

Fragrance is the most common cause of cosmetic contact dermatitis; preservatives are another common cause of cosmetic allergy. Preservatives help prevent bacterial or fungal growth in products containing water, but particular preservatives can trigger reactions in people allergic to them. Lanolin is another possible trigger. Urea and acidic preparations can sting scratched or cracked skin, which is not the same thing as proving an allergy.26

Skin care marketed as natural or clean can also cause contact reactions. Treat 'natural' and 'clean' as marketing words, which look more qualified in quotation marks.5

What should I do now?

1. 1Stop applying the suspected lotion. Avoid further exposure rather than continuing through a visible rash.
2. 2Rinse the affected skin with plenty of warm water to remove remaining product.
3. 3Note where the rash appears and what else touches that area. Clothing dyes, fabrics and other skin care products can also cause contact dermatitis.
4. 4Choose a replacement labelled 'fragrance free' rather than 'unscented'. Unscented products can contain fragrance that masks other smells.
5. 5Ask a pharmacist about a suitable moisturizer if the rash is troubling you. Moisturizers can help dry skin repair itself, even when one particular lotion caused the problem.

If an allergy is identified, avoid that ingredient in other products too. Apply a tolerated moisturizer immediately after bathing; slightly dry skin may only need an application at night, while very dry skin needs more frequent moisturizing.236

How long will the rash last?

Mild contact dermatitis can clear within days after avoiding the trigger, but many cases take 2 to 3 weeks. Itching can improve before the visible rash disappears. A rash that remains after stopping lotion does not immediately rule the lotion out, because allergic reactions can persist for weeks after exposure ends.14

When should I get medical help?

See a doctor for a severe, persistent, recurring or spreading rash, or symptoms that do not improve with treatment. Seek medical attention for possible infection, including warmth, tenderness, pus or fever. Trouble breathing requires emergency help immediately.134

A dermatologist can arrange patch testing, which places possible allergens on the skin and checks for delayed reactions over several visits. This helps identify allergic triggers; it is not a test for irritant dermatitis. Treatment can include prescribed steroid creams or ointments. Use these only as directed, without increasing the amount or frequency yourself.14