Acid nappy rash: causes, care and warning signs

Moisture, friction and digestive enzymes weaken the skin barrier. Frequent or loose stools can intensify irritation, leaving red, tender skin on the areas that touch the nappy.

Irritant rash tends to affect the buttocks, genitals and lower abdomen while deeper skin folds may be less involved. A bright red rash extending into the folds with small separate spots can fit yeast overgrowth, which may follow irritation or antibiotic use.

Other conditions can resemble nappy rash, including eczema, bacterial infection and reactions to wipes or fragranced products. The appearance, distribution and baby's general wellbeing help a clinician distinguish them.

Change wet or soiled nappies promptly. Clean with lukewarm water and soft cotton or a fragrance-free wipe, then pat rather than rub. Allow brief nappy-free time and apply a thick barrier ointment to clean, dry skin at each change.

Avoid talcum powder, antiseptics, perfumed products and exfoliating acids on the area. Do not use an adult steroid, antibiotic or antifungal cream unless a healthcare professional confirms it is suitable for the baby's age and the rash pattern.

Seek prompt advice if the baby has fever, seems unusually sleepy, feeds poorly, has fewer wet nappies, or the rash is rapidly spreading. Blisters, open sores, pus, crusting, bleeding or marked swelling also need assessment.

Contact a clinician if careful barrier care is not settling the rash, it repeatedly returns, or you suspect thrush. A very young infant who appears unwell should be assessed urgently rather than treated only at home.

Tell the clinician when the rash began, whether stools have changed, which nappies and wipes are used, and every cream already applied. Ask whether the pattern is irritant, yeast-related or another diagnosis, and how each prescribed product should be used.