pH The rise in pH increases the activity of fecal proteases and lipases, which can damage skin C albicans is found on the skin in 40% of infants with active diaper dermatitis within 72 hours of the appearance of the rash Because studies show that this organism is present in less than 10% of infants without diaper dermatitis, it may be playing a significant role Sources of C albicans include the GI tract and secondary implantation from a mother with candidal vaginitis FIGURE 69.12 Distribution of atopic eczema at various ages FIGURE 69.13 Infant with irritant/contact diaper dermatitis Another consideration is the predisposition of certain individuals to react more easily and negatively to varying irritants There are instances of true allergic contact dermatitis from baby wipes and dyes and fragrances found in diapers Allergies to dyes usually occur at the waist band, the area that fits tightly around the leg, and in the center of the diaper, sparing the folds If this is a concern, then switching to dye-free and fragrance-free diapers and using water or soft cloths with water instead of traditional disposable wipes may help Generally, infants with an atopic or seborrheic predisposition are at greater risk for the development and persistence of diaper dermatitis Differentiation of the various types of diaper dermatitis is difficult Clues from the history and physical examination are necessary when characterizing the cause of this problem The different types of diaper rashes include occlusion dermatitis, atopic dermatitis, seborrheic dermatitis, candida diaper dermatitis, and mixed dermatitis Acrodermatitis enteropathica, which is caused by zinc deficiency, psoriasis, and Langerhans cell histiocytosis, should also be considered in the differential diagnosis for diaper dermatitis that is persistent or does not respond to antifungals and antiinflammatory medications Treatment is determined by the cause of the dermatitis In general, optimized skin care, which includes decreased frequency of washing, use of mild soaps, and use of barrier emollients, will help with any diaper dermatitis With occlusive dermatitis, avoidance of tightly fitting diapers, plastic-covered paper diapers, and rubber pants is important When atopic dermatitis is present, the use of topical steroids is necessary It is important to avoid fluorinated or other potent steroids in the diaper area because occlusion by the diaper enhances the steroid effect and is more likely to produce skin atrophy and striae Antifungal–steroid combinations should also be avoided for these same reasons Therefore, 1% or 2.5% hydrocortisone cream or ointment no more than twice daily over a short period (5 to days) is recommended Hydrocortisone (1% or 2.5%) is also effective for seborrheic diaper dermatitis and can be used intermittently With candidal diaper dermatitis, the use of preparations such as econazole, miconazole, or nystatin twice daily is effective If thrush is also present, oral nystatin suspension, 200,000 units (2 mL) four times a day for days, is advisable This medication will also be useful if the infant is seeding C albicans from the GI tract onto the skin of the diaper area Secondarily infected dermatitis, such as bullous impetigo, should be treated with the appropriate systemic antibiotics or in some cases topical antibiotics Atrophic Patches Aplasia Cutis Aplasia cutis is a congenital defect that is characterized by localized absence of epidermis and dermis and, sometimes, subcutaneous fat It generally occurs on the scalp (80% near the hair whorl) but can occur on any location of the body Right after birth, aplasia cutis can appear as a scar or as a weeping, granulating oval or circular defect Small defects are the most common but larger ones sometimes occur and may extend to the dura or meninges Some lesions may present with an almost bullous appearance and when surrounded by dark hair or thicker hair (hair collar sign) may represent a form of neural tube defect Patients with these lesions should undergo an MRI of the brain to look for underlying connection to the brain Congenital absence of skin can also be seen with epidermolysis bullosa Antithyroid drugs, most notably methimazole, have been implicated in some cases of aplasia cutis congenita Indurated Plaques Subcutaneous Fat Necrosis Subcutaneous fat necrosis is a condition seen in usually term infants with the development of freely mobile nodules and plaques with or without redness They usually appear within the first weeks of life and are usually limited to areas of trauma or ischemia during delivery These can be asymptomatic or mildly tender Risk factors include high birth weight, prolonged labor, neuroprotective cooling, and other ischemia The most common locations are the back, buttocks, and cheeks Lesions resolve spontaneously in weeks to months Mild atrophy of the skin may be noted after resolution Complications include hyper- or hypocalcemia, lactic acidosis, high levels of ferritin, and transient thrombocytopenia; hypercalcemia is the most common For extensive lesions, serum calcium, phosphorus, parathyroid hormone, and vitamin D levels should be monitored and patients should be observed closely for irritability, vomiting, anorexia, renal failure, or failure to thrive in the first months Pamidronate and low-calcium formula are used in severe cases In most cases, reassurance is all that is needed Vascular Patches/Plaques and Hamartomas Acute Hemorrhagic Edema of Infancy Acute hemorrhagic edema of infancy is a distinctive, cutaneous small-vessel leukocytoclastic vasculitis of young children Dark purple or pink in color, somewhat annular patches and plaques, without surface change, occur mostly on the face and extremities ( Fig 69.14 ) Infants otherwise look well and are usually afebrile or at most have a low-grade fever Visceral involvement is uncommon, and spontaneous recovery usually occurs within to weeks without sequelae The main differential diagnosis is Henoch–Schönlein purpura