Monograph to the June 2007 issue

Current Issues in Pediatric Care: Infants

Skin conditions in infancy: common dermatitis and complex manifestations

Common dermatologic conditions are a frequent cause of pediatric office visits each year. Although most cases of skin eruptions are self-limiting, some advance to present significant irritation for both patients and their families. Beyond simple itchiness or irritation, open fissures on the skin are vulnerable to secondary microorganism infection.

Atopic dermatitis, also called eczematous dermatitis and atopic eczema, is perhaps the most common skin condition in infancy. Known as the “itch that rashes,” infantile atopic dermatitis is categorized by severe pruritus and a relapsing course of skin eruptions. Frequent irritation of lesions by scratching can disrupt the skin barrier, which may facilitate Staphylococcal or Streptococcus infection.¹ Likewise, secondary nickel hypersensitivity can complicate and further exacerbate the primary complaint, leading to more itchiness and, in turn, more skin-barrier disruption.

Diaper dermatitis is another common skin irritation in infants. Limited to the diaper area and caused by irritation of the skin by retained feces, urine, soap or detergents,^2-4 diaper dermatitis can usually be treated with over-the-counter medications and palliative therapy. When the affected skin is disrupted, however, Candida infection can develop, and topical antifungals may be indicated. There has been some suggestion that topical steroids may be indicated; however, the evidence in the medical literature is inconclusive as to the utility or safety of topical steroids in the diaper area.

Building a differential diagnosis

Recognizing and describing the reaction pattern of a skin eruption is key to reaching a diagnosis.⁵ The two most common reaction patterns seen in infancy are papulosquamous and eczematous. In papulosquamous eruptions, such as pityriasis rosea, psoriasis, tinea corporis or versicolor, lichen planus or candidiasis, the primary lesion(s) consist of papules or macules and scaling.

The eczematous reaction pattern is more varied.⁵ The eczematous reaction pattern occurs in three stages. In the acute stage, lesions appear as erythematous juicy papules, plaques or weeping vesicobullous lesions. In the subacute stage, crusts, excoriations, drying papulovesicles, pustules, and erythema are seen. In the chronic stage, lichenification is seen. Other skin eruptions follow reaction patterns that differentiate them from more common skin outbreaks (Table 1).

Table 1 Nearly all skin conditions can be classified by their reaction pattern. Another differentiating factor in skin outbreaks it their etiology.

One should attempt to determine the etiology. For example, localized, erythematous skin eruptions on the diaper area suggest an exogenous irritation, e.g. feces or urine. An eczematous reaction around the navel may alert pediatricians to ask parents about sustained contact with nickel, perhaps from a snap or button in clothing.

Atopic dermatitis suggests an allergic diathesis. Sometimes the condition is not correctly diagnosed until more characteristic patterns recur at an older age. A family history of atopy or other allergic conditions, however, should suggest the possibility of atopic dermatitis.

Atopic dermatitis

It has been estimated that atopic dermatitis affects between 10% and 20% of infants in the United States, and occurs in about one third of families with a history of allergic rhinitis or asthma. The incidence of atopic dermatitis appears to be increasing.^6-9

The condition is often associated with elevated IgE levels.⁸ Atopic dermatitis, however, is more properly categorized as an inherited skin hypersensitivity reaction, because the condition can be outgrown, as opposed to allergy, which often can not.¹⁰

In infants, the typical presentation of atopic dermatitis is an acute or subacute pruritic eruption. The face, especially the cheeks, is often involved.

A 1994 study of 224 patients described the findings in atopic dermatitis as history of flexural involvement, history of dry skin, onset younger than 2 years of age, history of asthma, history of a pruritic skin condition and visible flexural dermatitis.^11-13 In the same study, age, sex, geographic location, social class and ethnic group were not predictive of a diagnosis of atopic dermatitis.

Although most infants will outgrow symptoms by age 2, a subset of patients will continue to have a recurrence of lesions that may spread to other areas of the skin.¹⁰ After 2 years of age, children with recurrent atopic dermatitis may present with more chronic symptoms, including lichenification and scaling on the face, neck, trunk and flexural aspects of the extremities. The reason for the change in presentation pattern on the extremities is not clear. Further, Dennie’s pleats, or Dennie-Morgan lines, which are lines or folds below the margin of the lower eyelid, are sometimes seen with atopic dermatitis.¹⁴

Differential diagnosis © Neil S. Prose, MD   © Neil S. Prose, MD © Centers for Disease Control and Prevention © Gavin Hart Figure 1. Atopic dermatitis can have a subtle presentation early in the disease course. In young children, skin lesions are frequently present on the face, especially at the base of the ear lobe (A). A relevant history will differentiate atopic dermatitis from contact dermatitis (B) and scabies (C), which frequently presents on the hands, an area where skin-to-skin contact with infected individuals is likely to occur. Skin eruptions in psoriasis (D) are markedly different.

Infantile atopic dermatitis should be differentiated from several conditions, e.g. contact dermatitis, scabies and psoriasis (Figure 1). Contact dermatitis can be categorized as irritant contact dermatitis (injury to the skin as a direct result of chemical exposure) or allergic contact dermatitis (a type IV or delayed hypersensitivity of the skin to an environmental allergen). A clinically relevant history of exposure may help determine the cause of contact dermatitis; otherwise, skin lesions may be morphologically indistinguishable from those associated with atopic dermatitis.

A history of exposure is also important in diagnosing scabies. Scabies, a mite infection caused by exposure to Sarcoptes scabiei, is usually spread by skin-to-skin contact among family members or people in long-term care facilities.¹⁵ Mites burrow into skin. Although pruritus is common to both atopic dermatitis and scabies, scabies is more typically present on hands, feet and axilla of infants, and occasionally burrow holes—where a fertilized female mite burrows through the skin to deposit eggs—can be found in the lesions. The lesions in infants tend to be more polymorphic than in older children and adults.

Psoriasis, which usually manifests in the second or third decade of life although infant onset may occur,¹⁶ is another condition that resembles atopic dermatitis. Psoriasis is generally less pruritic than atopic dermatitis and typically affects the extensor areas of the skin. Primary psoriasis lesions can also begin in the diaper area and can appear to be symptoms of irritant diaper dermatitis.

Complex atopic dermatitis

The frequent itching associated with atopic dermatitis can result in excoriation, which may disrupt the skin, resulting in infestation with fungi or viruses, or more commonly bacterial infection. Staphylococcus aureus is the main offender and may aggravate the underlying eczema.

Patients with atopic dermatitis may be prone to secondary skin hypersensitivity, especially to nickel from belt buckles or snaps on clothing. A follicular papular eruption is typical in these cases. Another concomitant condition is infectious eczematoid dermatitis in children with draining ear, which leads to crusting of the skin as pus oozes from the ear onto the skin.

Eczema herpeticum is a concern in patients with eczema because it causes significant morbidity and can be fatal due to untreated systemic involvement. Lesions can appear vesicular, papular, or umbilicated, and may mimic Staphylococcal or Streptococcal infection, which may also be follicular in presentation.

Irritant diaper dermatitis

Irritant diaper dermatitis is a common condition in infants, although it is not necessarily an indication of poor hygiene practices by the parents. Feces and urine in the diaper commonly induce superhydration of the affected skin, spurring release of bacterial enzymes that, in turn, release ammonia from urine.^2-4 Lotions or soaps used to clean the diaper area may similarly overhydrate the skin, causing the common skin eruption.

Diaper dermatitis is a rash confined to the diaper area, and in many cases the rash conforms to the shape of the diaper.¹⁷ In patients with noncomplex cases, creases around the legs are not affected (Figure 2). Lesions appear as erythematous and scaly, with possible papules or plaques, vesicles or bullous lesions.¹⁸ If untreated, fissures or erosions may form.

Typical and complex diaper dermatitis   ©2007, Wellcome Trust/ Custom Medical Stock Photo Figure 2. Common diaper dermatitis is confined to the diaper area (A). Children with diaper dermatitis may be prone to secondary Candida infection because they can have fissures on the protective skin barrier (B). Note the involvement of the flexural creases in the complex case.

A small percentage of diaper dermatitis is caused by allergy to dyes in disposable diapers.¹⁹ Use of disposable diapers still is preferred when possible, especially in children with skin sensitivities or a history of allergy—children who wear disposable diapers exclusively are less likely to develop irritant diaper dermatitis compared with children who wear cloth diapers exclusively or even occasionally.²⁰

Because irritant diaper dermatitis is confined to a specific area, it has a distinctive presentation. Still, other skin conditions should be ruled out before a diagnosis of irritant diaper dermatitis is made. Although infantile seborrheic dermatitis is usually associated with “cradle cap,” there may be genital or umbilical involvement.²¹ Seborrheic dermatitis, when it affects the scalp, most commonly causes eruptions where the auricle joins the scalp, while with atopic dermatitis, which more commonly affects the face, the inferior margin of the earlobe is most commonly affected (Figure 1a).

Infant onset of psoriasis is another concern. About 10% to 15% of patients with psoriasis have onset in infancy.²² Early onset of psoriasis may portend more serious later manifestations. Compared with irritant diaper dermatitis, psoriasis tends to be more papulosquamous, and lesions are often nummular.

Tinea, which tends to be accompanied by papulosquamous eruptions, should be ruled out by culture. A relevant history is important to determine the presence of tinea.

Secondary Candida infection

A leading concern in diaper dermatitis is secondary infection with Candida albicans. Secondary bacterial skin infection also may occur after irritant diaper dermatitis. Study findings vary on the incidence of C. albicans infection secondary to irritant diaper dermatitis; however, historical studies have shown the incidence of secondary fungal infection to be as high as 40%.^2,23

Lesions in secondary Candida infection after diaper dermatitis may appear beefy and red, and satellite pustules are common. Candida infection should be confirmed by a positive KOH. Use of antibiotics, amoxicillin in particular, has been identified as a potential risk factor for Candida infection.²⁵

Diaper dermatitis requires a stepwise approach to management, with first-line therapy usually involving over-the-counter lotions or ointments. In patients with confirmed fungal infection, however, a more aggressive strategy is needed. Topical antifungals are a popular choice, and a combination product (0.25% miconazole/15% zinc oxide/81.35% white petrolatum, Vusion Ointment, Barrier Therapeutics) may be a suitable option, providing antifungal activity in a palliative ointment vehicle (Table 2).

Table 2 Cure rates for infants with Candida infection secondary to diaper dermatitis Table 2. In a clinical trial enrolling infants with confirmed Candida infection secondary to diaper dermatitis, miconazole nitrate was superior to vehicle alone in producing both biological and clinical cure.28

In a clinical trial enrolling infants with confirmed Candida infection secondary to diaper dermatitis, miconazole nitrate was superior to vehicle alone in producing both biological and clinical cure.²⁶ In the trial, miconazole nitrate was well tolerated, and significantly, rates for discontinuation of study medication because of clinical failure was lower among infants treated with miconazole nitrate (4%) compared with the vehicle (47%).

Miconazole nitrate should be used only for 1 week, however, because use beyond 1 week has not been established.²⁷ While resistance is a class-wide concern for antifungal therapy, presently no known resistance has been reported. Topical steroids have been suggested for more severe cases of complicated irritant diaper dermatitis, although the FDA has advised against their use in infants because of the potential for adverse reactions.

Conclusion

Skin eruptions are a common occurrence in infancy. In most patients, outbreaks are self-limited and noncomplicated. Skin eruptions that persist or that do not appear to resolve, however, may warrant close monitoring, because some skin conditions can lead to a potentially serious complications.

References

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24. Honig PJ, Gribetz B, Leyden JJ, et al. Amoxicillin and diaper dermatitis. J Am Acad Dermatol. 1988;19(2 Pt 1):275-279.
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26. Vusion [package insert]. Princeton, NJ. Barrier Therapeutics, Inc. 2007.

[Introduction]
[Skin conditions in infancy: common dermatitis and complex manifestations]
[Identifying risk factors for severe RSV infection]

Copyright 2007, SLACK Incorporated. Revised 25 July 2007.