Nappy rash, candida, and patterns that should worry you

nappy rash · napkin dermatitis · irritant dermatitis · candidal nappy rash · diaper rash

Whether the skin creases are spared or involved tells you which it is - and the nappy area is also where non-accidental injury is found.

GPBand B

Red flags

Any bruise in a baby who is not yet independently mobile - NICE CG89 lists this first among the bruising features that should prompt suspicion of maltreatment, whatever the site, and most infants presenting with nappy rash are in exactly this group. Before escalating, satisfy yourself it is a bruise: dermal melanocytosis over the sacrum, buttocks or back is a normal finding in babies with brown and black skin, is more uniform in colour than a bruise, and is the classic benign mimic - see the neonatal rashes entry. Bruising in darker skin is also harder to see in the first place, so absence of visible bruising is not reassurance
Bruising, petechiae, burns, bite marks or injuries in the nappy area, perineum or genitals - these sites are rarely injured accidentally. Follow NICE CG89 and your local safeguarding process; a skin finding you cannot explain is a safeguarding assessment, not a dermatology one
Any injury inconsistent with the history given, or with the child's developmental stage
Delayed presentation, or an account that changes between tellings
Severe erosive or ulcerated disease, or failure to respond to appropriate treatment
An unwell or febrile infant, or skin involvement extending well beyond the nappy area

Recognise

On light skin

Irritant: shiny red confluent erythema over the convexities with sparing of the folds. Candidal: beefy red involvement including the folds, with a scalloped edge and satellite papules and pustules.

On brown and black skin

The distinction rests on redness in every textbook description and that is not available in brown and black skin, where an inflamed nappy area may look darker, violaceous, greyish or simply shiny. Use the anatomy, which is tone-independent: are the creases spared or involved, and are there satellite lesions beyond the main area. Feel for the moist, macerated texture of candidal involvement in the folds. Post-inflammatory hypopigmentation in the nappy area afterwards is common, can be extensive and alarming to parents, and is regularly mistaken for scarring or for steroid damage - explain it unprompted.

In any skin tone

Folds spared - irritant contact dermatitis, the common one
Folds involved, with satellite lesions - candidal infection
Soreness and distress at nappy changes
Consider other causes if it is severe, persistent or unresponsive: seborrhoeic dermatitis, psoriasis, atopic eczema, or rarely zinc deficiency
Look beyond the nappy area - a rash elsewhere changes the diagnosis

Distribution

Irritant dermatitis affects the convex surfaces in contact with the nappy - buttocks, genitals, lower abdomen - and characteristically spares the skin folds. Candidal infection does the opposite and involves the folds, with satellite lesions beyond the main area.

Photographs

Candida culture-positive nappy dermatitis. Two features separate this from a simple irritant nappy rash, and both are visible here. First, the beefy red eruption **runs right into the depths of the skin creases** - irritant rash spares the folds, because the nappy and the urine never reach them. Second, there are **satellite lesions**: discrete small red papules and pustules scattered on normal skin well beyond the main area. Candidal nappy rash needs a topical antifungal; barrier cream alone will not clear it. Look in the mouth too, since oral thrush often goes with it. On brown and black skin the beefy redness reads as a deeper brown or violet, and the satellite lesions - being raised and palpable - become the more reliable sign. The left panel of a two-panel published figure.
Fitzpatrick II (Fitzpatrick type estimated from the photograph, not stated by the source) · Siegfried EC, Hebert AA, Journal of Clinical Medicine · Siegfried EC, Hebert AA. Diagnosis of Atopic Dermatitis: Mimics, Overlaps, and Complications. J Clin Med 2015;4(5):884-917, Figure 19 (left panel, via Wikimedia Commons) · CC BY 4.0 · adapted

Provenance for every photograph in this library: image licences. How much of the corpus still has no darker-skin photograph: skin tone coverage.

Mimics

Atopic eczema and infected eczema — Eczema usually spares the nappy area because it is moist and occluded, so florid nappy-area eczema should prompt a rethink
Impetigo — Bullous impetigo favours the nappy area in infants
Benign neonatal rashes - the reassurance set — In the newborn, nappy-area lesions have their own benign differential
Staphylococcal scalded skin syndrome — SSSS begins in the flexures and can be mistaken early for a severe nappy rash - but the child is febrile and the skin shears

What to do in the ED

Decide irritant versus candidal on whether the folds are involved, and treat accordingly - barrier preparation and nappy-free time for irritant, topical antifungal for candidal
Advise frequent nappy changes, gentle cleansing, and generous barrier application
For a rash that looks inflamed and is causing discomfort in a child aged 1 month or over, CKS supports hydrocortisone 1% cream in addition to the barrier preparation - a thin layer once a day until symptoms settle or for a maximum of 7 days, with the barrier applied a few minutes afterwards. This is ordinary primary-care prescribing, not a specialist decision. Where candida is suspected or confirmed on swab, CKS prescribes a topical imidazole (clotrimazole, econazole or miconazole) and advises against a barrier preparation until that infection has settled
Examine the whole child undressed, every time, in good light. The nappy area is one of the commonest sites of inflicted injury, and a nappy rash consultation is an opportunity to look properly. Mind the Gap notes that increased melanin makes immediate bruising hard to see - it may only become obvious as it darkens to purple, brown or black, and the yellow of an older bruise is more subtle too - so compare both sides and inspect closely rather than relying on a glance
If anything raises a safeguarding concern, follow NICE CG89 and the local child protection process, seek senior review, and document the findings and the history verbatim
Arrange follow-up for anything severe, persistent or atypical rather than repeatedly re-treating

Disposition

Treat and discharge with GP follow-up. Any safeguarding concern requires senior review and the local child protection pathway before the child leaves.

Safety-netting

Change nappies frequently, let the skin have time without a nappy, and apply the barrier cream thickly at every change. Return if the rash spreads beyond the nappy area, if it is not improving after a week of treatment, if the skin breaks down or bleeds, or if the child becomes unwell or feverish. Pale patches left behind afterwards are not scars and will even out with time.

Local variation

Safeguarding referral routes and documentation requirements are local; know yours before you need them.

Sources

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