Newborns and infants are susceptible to the occurrence of contact dermatitis in the diaper area, both in the irritative (ICD) and allergic (ACD) forms, due to constant exposure to their fecal waste, urine, and hygiene products.1

In this context, the use of wet wipers allows the cleaning of children regardless of the circumstances, speeding up and facilitating its practice in any location. These products consist of pieces of fabric soaked in an aqueous emulsion or oily lotion. Their use, however, can lead to adverse events and, therefore, care should be taken regarding their composition.2

The aim of the present work was to evaluate the characteristics of wet wipes commercialized in the city of São Paulo, Brazil, through the analysis of their pH values and composition.

Forty-two samples of wet wipers were acquired (from different locations and at variable prices) and cataloged. Each brand was analyzed separately in a reference laboratory.

Centrifuge tubes with 14 mL filters (Amicon™ Ultra-4 Centrifugal Filters) were used. The wipers of each brand were cut and positioned in a porous membrane filter with ultrafiltration capacity, in order to fill it completely. Each tube was identified and centrifuged (Eppendorf Centrifuge 5810 R™) for 30 minutes at 4,000 rotations per minute, which was repeated five times. At the end of the process, the amount of 2 mL of the aqueous solution was obtained from each wet wipe, which was then submitted to pH analysis using an appropriately calibrated benchtop pH meter (QUIMIS™ - Q400AS).3

The obtained pH measurements ranged from 3.53 to 7.43 (Table 1). Values ​​between 5.5 and 7.0 were found in 18 products (43%), a range considered to be ideal, close to the pH of the skin. However, more than half of the samples (54.7%) showed values ​​below this level, and one sample was >7.0. Products with a pH different from that of the skin can cause changes in the skin barrier functions: the lower ones act as irritants, and the higher ones inhibit the activity of proteases, making lipid synthesis difficult.4

The packaging of the products was also analyzed to verify the composition described on the labels by the manufacturers, specifying surfactants, preservatives, and fragrances (Table 2, 3 and 4).

Surfactants are compounds added to hygiene products that have detergent and foaming power. The most common was cocamidopropyl betaine, present in 57.1% of the products. This is a substance with widespread use due to its low cost, good cleaning capacity, moderate antimicrobial activity, non-toxicity, and compatibility with different pHs. However, studies have demonstrated its allergenic capacity, including in children.2,5

Preservatives are added to ensure durability, avoiding contamination after the package is opened. In the analyzed products, phenoxyethanol was the most commonly used. It is a safe preservative, with a broad antimicrobial spectrum and low capacity to induce ACD, recommended for products to be used in children. On the other hand, the presence of preservatives with high allergenic capacity was observed, such as methylisothiazolinone and formaldehyde-releasing agents (Bronopol, DMDM ​​hydantoin and Diazolidinyl urea).6

The presence of parabens was observed in several of the analyzed products. Although they are controversial because of their possible relationship with breast cancer, they have a low allergenic capacity.2 Their relationship with cancer has never been clarified and their use is allowed in Europe and the USA, since their estrogenic activity seems to be very low. In Brazil, their use is authorized by the Brazilian Health Surveillance Agency (Agência Nacional de Vigilância Sanitária – [ANVISA]) according to Resolution n. 29/2012.7,8

Fragrances are products that often cause ACD. In this evaluation, 104 fragrances were found, with an average of 2.47 per product. The designation “perfume” was found in 29 (69%) products, a term used for components that do not require discrimination on the label as they are within the limits established by ANVISA, which, however, does not eliminate the risk for ACD. Only nine products (21.4%) were considered “fragrance-free”, after the components were evaluated.2,9

Wet wipers represent a great advance as they are very practical for hygiene but they have the potential to cause adverse events. Thus, their use should be assessed, especially in atopic children or children with skin lesions in the diaper area.10