Aetiology
Nappy rash is most likely to be due to irritant contact dermatitis. The key irritants are moisture from urine and faeces as well as faecal enzymes (ureases, proteases, and lipases). Other potential irritants include nappy components, friction produced by nappies themselves, carer's repeated wiping of the area, or application of baby care products.[7] Components of disposable nappies that have been implicated as potential antigenic triggers include dyes, fragrances, rubber, glue, and other chemicals used in the manufacturing process. Preservatives found in toilet tissues can also be sensitisers.[8]
Infections can exacerbate or cause nappy rash. The main infectious aetiologies include Candida albicans, Staphylococcus aureus, and enteric organisms. Other infectious agents implicated include coxsackie virus, herpes simplex virus, and HIV; parasites such as pinworms and scabies; and other fungi leading to tinea corporis.
Underlying dermatological disorders, such as allergic contact dermatitis, seborrheic dermatitis, psoriasis, granuloma gluteale infantum, lichen sclerosis, and infantile granular parakeratosis, are associated with the development of nappy rash.
Unusual aetiologies include nutritional deficiencies, cystic fibrosis, urea cycle defects, immunodeficiencies, and histiocytosis.
Pathophysiology
Faecal enzymes and moisture from urine and faeces serve as triggers of an immunological reaction in the occluded nappy area. The increased pH of the skin associated with nappy-wearing further activates the enzymes.[9] The resultant inflammatory reaction due to pro-inflammatory chemo- and cytokines, leads to skin breakdown.[10] Allergic contact dermatitis involves an immunological response that produces rash within 12-24 hours after re-exposure to the offending agent.[11]
Use of this content is subject to our disclaimer