Looking at the spectrum of diaper dermatitis

Diaper dermatitis is a common presentation seen in dermatology. The differential diagnosis is broad and varies based on numerous risk factors, including patient age, gastrointestinal disorders, diaper hygiene practices, diaper breathability, and genetics. It is essential that pediatricians and dermatologists recognize the various forms of diaper dermatitis to effectively diagnose and treat it. The following 5 instructive cases of diaper dermatitis include the differential diagnosis (Table) and treatment options.

Table

Figure 1. Psoriasis

Figure 1

This 18-month-old boy with a family history of psoriasis presented for evaluation of an erythematous rash on the scrotum, suprapubic skin, and perineum, consistent with infantile psoriasis. Similar to adult psoriasis, infantile psoriasis presents as well-defined, often symmetrically dis- tributed erythematous papules and plaques. In contrast to psoriasis in adults, psoriatic plaques in childhood tend to be thinner, smaller, and less scaly and are more likely to develop on the face, trunk, and flexural areas, although they can develop on any skin area. In young children, infantile psoriasis is often diagnosed with a diaper rash that is unresponsive to irritant diaper dermatitis treatment.

PREVALENCE. Psoriasis affects approximately 2% to 3% of the population worldwide, and it is estimated that up to half of cases begin before age 20 years. The incidence increases with age. Results of one study showed that the total rate of psoriasis in children under 18 years old was 0.71%, with rates increasing linearly from 0.12% at 1 year of age to 1.2% by 18 years.¹ Findings of another study were similar, showing a prevalence of 0.55% in children aged 0 to 9 years compared with 1.37% in patients aged 10 to 19 years.²

DIFFERENTIAL DIAGNOSIS. Making a diagnosis of psoriasis is often more difficult in children because of atypical characteristics. Lesions in children may be thinner, softer, less scaly, and less well-defined than in adults.³ The differential diagnosis should include tinea corporis/cruris, atopic or nummular dermatitis, irritant contact dermatitis, seborrheic dermatitis, Candida dermatitis, and inverse pityriasis rosea.

WORK-UP. Diagnosis of infantile psoriasis is often clinical and, in unclear cases, can be aided by biopsy; however, biopsy is often not necessary and should be avoided in uncomplicated cases. Histology is similar to that of adult psoriasis and would reveal neutrophils overlying parakeratosis, loss of the granular cell layer, variable spongiosis, and elongated rete ridges.

TREATMENT. First-line therapy for infantile psoriasis is topical corticosteroids. Medium- to high-potency topical steroids can be used up to 4 weeks during the initial flare and then up to 2 weeks for subsequent flares.⁴ Using topical corticosteroids in combination and rotation with nonsteroidal topicals such as topical calcineurin inhibitors, vitamin D analogues, tar, and keratolytics can optimize efficacy while reducing the risk of adverse effects. It is important to know the ages of approval for steroid-sparing agents. Calcipotriene is approved for children 4 years or older, and topical calcineurin inhibitors are approved for patients 2 years or older. Crisaborole (Eucrisa) can be considered in patients 3 months or older. Phototherapy can also be considered for extensive or refractory disease. For moderate to severe plaque psoriasis in children, systemic therapy should be considered. Etanercept (Enbrel) is approved for children 4 years or older; ustekinumab (Stelara), ixekizumab (Taltz), and secukinumab (Cosentyx) are all approved for children 6 years or older. Studies have shown significant improvements in quality of life and psoriasis area and severity index scores for children with moderate to severe plaque psoriasis on systemic immunomodulators.⁵ Pediatricians should monitor patients for comorbidities associated with psoriasis, including obesity, hypertension, hyperlipidemia, rheumatoid arthritis, and diabetes. The patient in the vignette responded well to topical steroids.

Figure 2. Jacquet dermatitis

Figure 2

This 6-month-old girl presented with an erosive diaper rash following diarrhea with viral gastroenteritis. These findings were consistent with Jacquet erosive diaper dermatitis. Jacquet dermatitis is a rare, severe form of irritant diaper dermatitis characterized by ulcerated or eroded papules and nodules in the genital and perianal areas. It is typically associated with frequent loose stools, infrequent diaper changes, and poor hygiene. It is also more common in patients with chronic diarrhea or incontinence.

DIFFERENTIAL DIAGNOSIS. Milder forms of irritant diaper dermatitis often occur in infants with short episodes of loose stools associated with viral gastroenteritis and administration of oral antibiotics for otitis media and other infections. The differential diagnosis for severe erosive diaper dermatitis includes perianal pseudoverrucous papules and nodules, granuloma gluteale infantum, diaper dermatitis with superimposed bacterial and fungal infections, cutaneous Crohn disease, Langerhans cell histiocytosis, and acrodermatitis enteropathica.

WORK-UP. Secondary infection with Candida and bacteria is common in Jacquet dermatitis. Potassium hydroxide (KOH) preparation and bacterial culture can be performed to help guide antimicrobial therapy. If the patient fails to respond to therapy or has systemic findings, biopsy and additional laboratory tests may be indicated.

TREATMENT. Jacquet dermatitis treatment is similar to that of uncomplicated irritant diaper dermatitis, with the goal to reduce contact of the skin to urine and feces. This is accomplished through frequent diaper changes, use of diapers lined with absorbent gel materials, and application of barrier ointments. Low-potency topical steroids can also be used to reduce inflammation. Topical antifungal/antibacterial agents may be required in the case of secondary infection. Severe cases may require oral antibiotics and/or oral corticosteroids.

Figure 3. Staphylococcal pustulosis

Figure 3

This 7-month-old boy was brought to the clinic for pustules in the diaper area. These findings were consistent with staphylococcal pustulosis, a relatively uncommon manifestation of infection with Staphyloccus aureus. It can be difficult to diagnose because there is a wide differential for pustular eruption in infants, which includes both infectious and noninfectious etiologies. It is important to be able to distinguish benign causes from more serious causes that require additional management.

DIFFERENTIAL DIAGNOSIS. Noninfectious causes of pustules in an infant include erythema toxicum neonatorum, transient neonatal pustular melanosis, neonatal acne, and neonatal pustular psoriasis.⁶ In this case, some of those conditions could be ruled out based on timing. Erythema toxicum neonatorum typically affects full-term infants and presents within 1 to 2 days of birth. It is self-limited and usually resolves by 2 weeks of age. Neonatal pustular melanosis affects 0.2% to 4% of neonates, with a higher prevalence in Black babies. It usually occurs within a few days of birth and resolves spontaneously over a few weeks. Neonatal acne and pustular psoriasis have a wider range of age presentations. Neonatal acne presents as pustules as well as open and closed comedones that are usually limited to the face. It can occur within 3 to 16 months of age, although it usually appears within 3 to 6 months and resolves by 3 to 4 years. Neonatal pustular psoriasis is rare but can occur at any age and has a varied presentation. Pustules typically develop symmetrically and can occur on any area of the body, with a predilection for the diaper area and skinfolds.

Infectious causes include herpes simplex infection and candidiasis. Cutaneous manifestations of vertical herpes simplex virus (HSV) infection have been reported but are relatively rare and occur within a few days of life. Anogenital HSV infection in older babies and toddlers is also rare; it has additional implications and can be a sign of abuse. Candidiasis usually presents on a base of erythema with erythematous macular satellite lesions, neither of which is seen in this case.

To confirm the diagnosis, Gram stain and culture of the pustule fluid can be performed. Gram stain is often negative even in the setting of positive cultures and should not be used alone to rule out staphylococcal pustulosis. HSV polymerase chain reaction can be performed concomitantly if suspected.

WORK-UP. Biopsy typically does not play a role in the diagnosis of staphylococcal pustulosis. Although biopsy is often not performed for these lesions, histology would show subcorneal pustules with neutrophils and acantholysis.

TREATMENT. Limited skin disease can be treated with topical mupirocin ointment. The patient in the vignette responded well to this regimen. Patients with systemic symptoms or more widespread disease may require a course of oral antibiotics. Penicillinase-resistant antibiotics such as amoxicillin are usually sufficient. Methicillin-resistant S aureus (MRSA) is relatively uncommon in children. However, coverage for MRSA with antibiotics such as clindamycin and trimethoprim/sulfamethoxazole should be considered in regions with high resistance rates.

Figure 4. Seborrheic dermatitis

Figure 4

This 3-month-old boy presented for evaluation of an erythematous rash in a diaper distribution; findings were consistent with seborrheic dermatitis. This benign, self-limited condition presents as salmon-colored plaques with greasy scales and typically occurs within the first 3 months of life. Unlike seborrheic dermatitis in adults, which takes on a chronic course, seborrheic dermatitis in children is self-limited and usually resolves without treatment within the first 9 to 12 months of life. Many parents are familiar with the term cradle cap, which is infantile seborrheic dermatitis of the scalp, but the condition can also present on the face, axillae, inguinal folds, and trunk. When it occurs on the face, it tends to involve the eyebrows, nasolabial folds, and hairline. Lesions on the trunk usually involve the lower abdomen and are more sharply demarcated than those seen elsewhere on other body.

DIFFERENTIAL DIAGNOSIS. The differential diagnosis for symmetric, well- demarcated erythematous patches and plaques on a baby’s lower abdomen includes psoriasis, candidiasis, atopic dermatitis, contact dermatitis, and nutritional deficiency. Contact dermatitis is less likely when the skinfolds are affected. It is often difficult to distinguish atopic from seborrheic dermatitis in young children, and there can be overlap of the 2 conditions. However, seborrheic dermatitis is not usually pruritic, and atopic dermatitis typically spares the groin and axillae in young children.

WORK-UP. Diagnosis is usually made by history and physical exam alone. In cases where the diagnosis is not clear or the patient has an unusually prolonged course or lack of response to treatment, biopsy can be performed. Seborrheic dermatitis and psoriasis have similar histopathological findings, with a few key differences. Mounds of parakeratosis with neutrophils and clubbed and evenly elongated rete ridges are seen more often in psoriasis. Neutrophilic follicular scale/crust, shoulder parakeratosis, and lymphocytic exocytosis are seen more often in seborrheic dermatitis.⁷ A KOH preparation can be performed to rule out candidiasis. Patients with infantile seborrheic dermatitis are otherwise healthy and do not require additional laboratory monitoring.

TREATMENT. The mainstay of treatment for seborrheic dermatitis in infants consists of emollients that help loosen the scale, which can then be gently wiped away with a cloth. Because this is a self-limited disease that resolves without treatment, the risk to benefit ratio of additional therapies needs to be considered. Furthermore, treatments for seborrheic dermatitis in children have not been studied extensively for safety or efficacy, and it is unclear whether these interventions alter the course of the condition.⁸ Short courses of low-potency topical steroids also can be used. Calcineurin inhibitors and antifungal shampoos are not approved for use in children younger than age 2 years, so they should be avoided. The patient in the vignette responded well to emollients and topical steroids. He was able to discontinue therapy and did not have recurrence on follow-up a few months later.

Figure 5. Candidiasis with irritant dermatitis and candidiasis pustules

Figure 5

This girl between 5 and 6 months of age presented with a red rash in a diaper distribution. Findings showed erythematous papules coalescing into plaques, satellite lesions, and a few scattered pustules consistent with candidiasis, which usually presents as red erythematous papules, plaques, and peripheral satellite lesions in the groin with a predilection for skinfolds. Pustules, vesicles, and erosions can also be seen.

DIFFERENTIAL DIAGNOSIS. The differential diagnosis for an erythematous rash with plaques, papules, and pustules in a diaper distribution includes psoriasis and contact dermatitis.

WORK-UP. For this case, KOH preparation was performed and showed yeast and pseudohyphae. Although biopsy is often not required, histology would show neutrophils and vertically oriented pseudohyphae in the stratum corneum. Crusting and hyperkeratosis are also commonly seen.

TREATMENT. Treatment with anticandidal antifungals such as nystatin and clotrimazole is required to achieve clearance. This patient responded well to topical antifungals and barrier cream therapy. Parents also can be educated to use breathable disposable diapers to reduce the rate of recurrence—the survival of Candida is reduced more than 50% in breathable vs nonbreathable diapers.

References

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2. Gelfand JM, Weinstein R, Porter SB, Neimann AL, Berlin JA, Margolis DJ. Prevalence and treatment of psoriasis in the United Kingdom: a population-based study. Arch Dermatol. 2005;141(12):1537-1541. doi:10.1001/archderm.141.12.1537

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8. Victoire A, Magin P, Coughlan J, van Driel ML. Interventions for infantile seborrhoeic dermatitis (including cradle cap). Cochrane Database Syst Rev. 2019;3(3):CD011380. doi:10.1002/14651858.CD011380.pub2