Itching and a rash after a new sanitary pad, laundry or tights are easy to blame on an "allergy to everything." In reality, the skin reacts in different ways: sometimes it is direct irritation, sometimes a true allergy. What to do next depends on the mechanism.
What contact allergy to household items is
Contact dermatitis is inflammation of the skin after direct contact with a substance. There are two mechanisms. Irritant contact dermatitis is the most common: it is not the immune system but the skin's reaction to an aggressive substance or friction. Allergic contact dermatitis is the immune system's response to a specific allergen and is less common.
Irritants include acids, alkaline materials such as soap and detergents, fabric softeners, and solvents. Mild chemicals cause a reaction after repeated contact, aggressive ones almost immediately. The risk is higher with atopic dermatitis.
With allergy the logic is different: there is no reaction on first contact. A substance can be tolerated for years, and then an allergy suddenly develops — and stays. The reaction more often occurs after 24–48 hours, and the rash persists for weeks.
Allergy to sanitary pads and diapers: why it occurs
Sanitary pads and diapers stay in contact with the skin for a long time, and allergy to individual components can be caused by adhesives, fragrances and formaldehyde (as in other products); the exact culprit is determined only by a doctor. Rubber and latex can also cause allergy.
Irritation is simpler: prolonged contact with a wet diaper is a common cause of irritation. Friction can also irritate the skin. So an "allergy to a diaper" often turns out to be irritation from moisture.
Allergy to laundry detergent and fabric softener
Detergents and fabric softeners are among the common skin irritants. This leads to dryness, redness and roughness, especially on the hands and under tight fabric.
Allergy to household chemicals works differently: individual components, such as fragrances, can cause allergy. Fragrances are found in soap, cosmetics and moisturizers. A rash after laundry is a reason to read the ingredients.
Allergy to synthetics, clothing and adhesive plasters
Fabrics and clothing can cause allergy: both the material and the dyes. A rash appears where the substance touched the skin: a zipper, a bra hook, a button. Nickel and other metals produce exactly such localized spots.
Allergy to an adhesive plaster is a reaction to the adhesive base. Adhesives for false eyelashes have the same mechanism. The reaction is delayed: the rash appears a day or two later, when the plaster has already been forgotten.
How the skin reaction manifests and what the rash looks like
The skin itches, dries, cracks, and blisters appear. On light skin the area turns red, on dark skin it becomes dark brown, purple or gray. The hands and face are affected more often, but a reaction is possible anywhere the substance has reached.
An allergic rash consists of red bumps that may ooze, become crusted, and flake. With irritation, burning and pain are added, and cracks appear on the hands. A separate scenario is photosensitization: a reaction only where the sun has reached.
- More itching suggests allergy; burning and pain suggest irritation.
- A spot at the site of a plaster, zipper or bra hook — think of the material or adhesive.
- Dryness after washing and laundry is a typical irritant scenario.
- A reaction only at the site of contact indicates a contact mechanism.
How the cause is identified and when a doctor is needed
The diagnosis is made based on the appearance of the skin and questioning about contacts. For persistent or recurrent dermatitis, patch tests are done: patches with possible allergens are applied to the skin. At least three visits are needed — application, removal after 48 hours, and examination another two days later. For some metals, a visit on the tenth day is added.
See a doctor for persistent, recurrent or severe symptoms. A referral to a dermatologist is made if the cause cannot be found or the reaction does not respond to treatment. With severe itching, it is better not to delay a visit to the doctor.
Such a rash by itself is not a reason to call an ambulance. 103/112 — if the lesion is extensive, covers most of the body and is accompanied by malaise or an increase in body temperature.
This is a reference cheat sheet, not a substitute for a doctor's consultation: it is better to look for the cause of a rash together with a specialist.
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This content is for reference and does not replace a doctor's consultation. Medical disclaimer