Allergy to Chemicals: Chlorine, Alcohol and Formaldehyde

A skin reaction to bleach, alcohol or cosmetics often turns out to be contact dermatitis — local inflammation of the skin that occurs on direct contact with an irritant or allergen. The term "allergy to chemicals" is widely used in everyday speech, but from a medical standpoint it conceals two different mechanisms, and confusing them is undesirable.

What allergy to chemicals is

Contact dermatitis comes in two types. Irritant dermatitis, the most common, is caused by direct damage to the outer layer of the skin by acids, alkaline products, soaps, detergents, solvents and other chemicals; the immune system is not involved. Allergic dermatitis occurs when the skin meets a substance to which the body responds with an immune reaction; it is less common, and typical allergens are cosmetics, perfumes, dyes, metals such as nickel, preservatives and formaldehyde. On first contact there is usually no reaction: sensitization develops later, sometimes after months and years of use, and once it appears, the allergy persists for life.

Allergy to chlorine and chlorinated water: signs

Chlorine-containing products belong to household chemicals that most often cause irritant dermatitis specifically with frequent contact with water and detergents. Very aggressive substances cause a reaction after even brief contact, while milder ones do so on repeated contact. It manifests as dryness, redness, roughness, burning and itching; with prolonged exposure the skin becomes more inflamed, and cracks may appear on the hands. The reaction usually occurs several hours or days after exposure, and the rash may persist for weeks after contact ceases.

Allergy to bleach after cleaning and in the pool

The hands are affected most often: contact dermatitis most commonly occurs on the hands and face. In a pool, prolonged contact with water is added to the chlorine, and regular exposure to water and detergents is itself among the most common causes of irritant dermatitis. Symptoms include redness, dryness, itching, burning and soreness, and with a pronounced reaction — blisters and oozing. Parents often look for photos of similar rashes, but a diagnosis can only be made on examination by a doctor and after asking about contacts.

Allergy to alcohol and formaldehyde

Skin irritation is generally associated with solvents, whereas a reaction to formaldehyde and other cosmetic ingredients is allergic. Formaldehyde and its derivatives in shampoos, lotions and moisturizers are a known allergen. Allergens are also found in cosmetics, so a link between the rash and a specific product helps to suspect a reaction. An allergic reaction is often delayed: the rash appears 24–48 hours after application, so the culprit can be difficult to identify without analyzing the product's composition and patch tests.

What allergy on the hands from chemicals looks like

Contact dermatitis is most often localized on the hands and face. The skin looks dry, red and rough; in the allergic form the itching can be intense, and red bumps, oozing blisters, crusts, scaling and thickening appear; on light skin there is redness, on dark skin — dark brown, purple or gray shades. The affected area is warm and tender to the touch, and in the irritant variant pain is added to the burning.

How the cause of the reaction is determined and when to see a doctor

The diagnosis is made based on the appearance of the skin and by asking about contacts with substances. For prolonged or recurring dermatitis, patch tests are used: they are carried out over several visits, assessing the reaction after 48 hours and later, and for some allergens — on the tenth day; the test must be interpreted by a specialist. The doctor may also prescribe other examinations, such as a biopsy or a culture from the affected area. A doctor should be consulted for persistent, recurring or severe symptoms; a referral to a dermatologist is offered if the cause cannot be found or treatment does not help.

• Dryness, redness and cracks on the hands after cleaning or the pool
• Intense itching and oozing blisters a day or two after a new cosmetic product
• Rash on the face, neck or under jewelry
• Recurring episodes without an obvious cause

This condition by itself is not a reason to call an ambulance; 103 or 112 — for rapidly increasing sharp deterioration in well-being and difficulty breathing.

Contact dermatitis usually resolves if contact with the substance that caused it is eliminated, but it is not always possible to identify this substance on one's own. The material is for reference and does not replace a doctor's consultation: for persistent or recurring rashes it is wiser to see a specialist than to change products at random for years.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer