Nappy Rash

Nappy (diaper, napkin) rash is inflammation of the skin covered by a nappy. It is most common between 3 and 15 months, but it continues through the toddler years until the child is toilet trained (DermNet). Most nappy rash is irritant contact dermatitis. Urine and the occlusion of the nappy over-hydrate the skin. Faecal enzymes and bile salts break down the skin’s lipids and proteins. Urine and faeces together form ammonia, which raises the skin pH. Friction adds to the damage (DermNet). Stool frequency and pH rise when solids are introduced, and nappy rash becomes more common as a result. Diarrhoea, teething-related loose stools and antibiotics are other common triggers (DermNet; NHS). Pre-existing Atopic Dermatitis or Seborrhoeic Dermatitis predisposes to nappy rash (DermNet).

Nappy Rash [part-of] Irritant Contact Dermatitis Skin pH [relates] Nappy Rash Atopic Dermatitis [relates] Nappy Rash

Irritant vs candidal vs eczema vs others. The pattern tells you most:

• Irritant: shiny or blotchy redness, sometimes with dryness and scale, on the convex skin in contact with the wet nappy (buttocks, genitals, upper thighs). It spares the skin folds (DermNet). Chafing produces red erosions along the waistband and leg edges.
• Candidal (Candidiasis): deep “beefy” red patches that involve the creases, with small satellite red spots or pustules beyond the edge (DermNet; Türe Avcı et al., Children 2026). Candida is a frequent cofactor in irritant rash, especially if a rash persists more than a few days or follows antibiotics (Siegfried & Hebert, J Clin Med 2015).
• Atopic Dermatitis: dry, scratched plaques. AD typically spares the nappy area because the nappy keeps the skin humid, and the giveaway is eczema elsewhere, such as the cheeks, limbs and creases (DermNet; Healio; Türe Avcı 2026). A toddler with AD can still get irritant nappy rash on top, because their barrier is weaker (Healio).
• Seborrhoeic Dermatitis: salmon-pink, peeling patches in the folds, with cradle cap and armpit involvement, and little itch (DermNet).
• Psoriasis (“napkin psoriasis”): persistent, sharply edged, shiny red plaques that involve the folds and natal cleft and do not respond to usual care. There is often a family history (DermNet; Napolitano et al., Dermatol Ther 2022).
• Impetigo: blisters, pustules and honey crusts (DermNet).
• Rare causes: zinc deficiency (sharply bordered plaques that spare the folds, with a rash around the mouth and diarrhoea) and Langerhans cell histiocytosis (with petechiae) are red flags for referral (Siegfried & Hebert 2015; Napolitano 2022). A rash confined to the nappy area points away from AD. A rash in the nappy area that does not clear with good barrier care needs review (Türe Avcı 2026).

Candidiasis [worsens] Nappy Rash Nappy Rash [part-of] Differential Diagnosis of Toddler Eczema Psoriasis [relates] Nappy Rash Seborrhoeic Dermatitis [relates] Nappy Rash

Prevention and barrier care (first line). NHS and DermNet advice:

• Change wet or dirty nappies as soon as possible. Use absorbent disposables that fit well (not too tight), or liners with cloth nappies. Avoid plastic over-pants.
• Clean with water or fragrance-free, alcohol-free wipes, then pat dry. Allow nappy-free time.
• Apply a thin layer of barrier cream at every change: a protective ointment containing Petrolatum and/or zinc oxide.
• Avoid soap, bubble bath, baby lotion, talc and antiseptic creams (NHS). Fragranced wipes can irritate the skin, and wipe preservatives such as Methylisothiazolinone can cause allergic contact dermatitis (DermNet; NHS). DermNet notes that some small trials reported benefit from non-prescription Calendula or aloe products. However, Calendula is a Compositae plant, so these products carry a sensitisation risk in children with eczema.

Barrier Creams [prevents] Nappy Rash Petrolatum [prevents] Nappy Rash

When mild hydrocortisone, and when antifungal. If the skin stays inflamed despite barrier care, the NHS says a GP may prescribe a steroid cream for redness and soreness, an antifungal if thrush is suspected, or antibiotics for bacterial infection. DermNet specifies a mild topical steroid such as Hydrocortisone once or twice daily for 1–2 weeks, and a topical antifungal (clotrimazole, ketoconazole) once or twice a day if candida is suspected. Combined hydrocortisone-plus-antifungal creams are often used when both inflammation and candida are present. Strong steroids must not be used on a baby’s bottom. The nappy works like an occlusive dressing that increases steroid absorption (Eumovate leaflet), and potent steroids there risk stretch marks, skin thinning (Skin Atrophy) and tachyphylaxis (DermNet). Siegfried & Hebert also warn against chronic TCS use in the nappy area. Most paediatric case reports of HPA Axis Suppression involved superpotent clobetasol used for months on nappy-area eczema (Mooney 2015). US guidance lists low-potency topical steroids such as hydrocortisone for nappy dermatitis (AFP 2009), and prescription Clobetasone Butyrate (Eumovate) lists nappy rash as a use. However, US OTC hydrocortisone labels must say “do not use for the treatment of diaper rash” (FDA M017). The label restricts self-treatment rather than clinician-directed short courses.

Conflict: [DermNet, Napkin dermatitis, 2017; NHS nappy rash, n.d.; AFP 2009] support a short course of mild hydrocortisone for inflamed nappy rash. [FDA OTC monograph M017] requires OTC hydrocortisone labels to state “do not use for the treatment of diaper rash”. Unresolved — add to open_questions.

Potent steroids under a nappy

The nappy works like an occlusive dressing. Use only a mild steroid such as hydrocortisone, for 1–2 weeks and only if a clinician advises it. Never use a stronger steroid prescribed for elsewhere on the body or for another family member in the nappy area.

Hydrocortisone [treats] Nappy Rash Clobetasone Butyrate [treats] Nappy Rash Nappy Rash [relates] HPA Axis Suppression Nappy Rash [relates] Skin Atrophy

When to get help. The NHS advises seeing a health visitor or GP if the rash does not go away, gets worse or spreads, if the baby has a fever, or if the baby is very uncomfortable. A rash that keeps recurring in the folds, a rash with sharply edged shiny plaques, or a rash that also appears around the mouth or with poor growth warrants review for candida, psoriasis or rarer causes (see Differential Diagnosis of Toddler Eczema and When to Refer).

Nappy Rash [precedes] When to Refer

Connections

• Hydrocortisone — low-potency steroid indicated for nappy dermatitis; US OTC label excludes it, source: AFP 2009; FDA M017
• Clobetasone Butyrate — Rx indication; nappy acts as occlusion, source: emc PIL 3807
• HPA Axis Suppression — nappy occlusion in most infant case reports, source: Mooney 2015
• Differential Diagnosis of Toddler Eczema — AD usually spares the nappy; rash confined there suggests irritant, candida, psoriasis or seborrhoeic, source: Türe Avcı 2026; Healio
• Irritant Contact Dermatitis — commonest mechanism, spares folds, source: DermNet 2017
• Candidiasis — fold involvement, satellite lesions; antifungal, source: DermNet 2017; Siegfried & Hebert 2015
• Seborrhoeic Dermatitis — salmon-pink fold patches with cradle cap, source: DermNet
• Psoriasis — persistent well-demarcated napkin plaques, source: DermNet; Napolitano 2022
• Barrier Creams — petrolatum/zinc oxide at every change, source: DermNet; NHS
• Petrolatum — barrier ointment base, source: DermNet 2017
• Skin pH — ammonia raises pH, source: DermNet 2017
• Methylisothiazolinone — wipe preservative allergy, source: DermNet 2017
• Calendula — small trials; Compositae sensitisation caveat, source: DermNet 2017
• Skin Atrophy — potent steroids on the bottom, source: DermNet 2017
• Impetigo — blisters/pustules in nappy area, source: DermNet 2017