A 1-week-old neonate is brought to the office due to a rash on his back and bilateral groin areas. The patient's mother first noticed it this morning as she was changing him; he seems to be doing well otherwise. He is breastfed every 2 hours and produces 8 wet diapers and 6 stools a day. There has been no fever. The patient sleeps most of the day and night in his crib, swaddled in a fleece blanket. Since birth, he has been using the same shampoo and bath soap and has been wearing the same brand of onesies underneath his pajamas. Other than vitamin D drops, the patient takes no medications. Temperature is 36.9 C (98.4 F), pulse is 115/min, and respirations are 45/min. On examination, he is awake, alert, and in no distress. Skin examination of the back is shown in the exhibit. The bilateral groin areas reveal similar lesions. The remainder of the examination is unremarkable. Which of the following is the most appropriate next step in management of this patient's rash?
Benign neonatal rashes | |||
Diagnosis | Onset | Clinical features | Management/resolution |
Erythema toxicum neonatorum |
|
|
|
Milia |
|
|
|
Miliaria rubra |
|
|
|
Neonatal pustular melanosis |
|
|
|
Neonatal cephalic pustulosis |
|
|
|
This patient who is dressed in multiple layers of clothing (onesies, pajamas) and spends most of the day and night swaddled in a fleece blanket most likely has miliaria rubra, or heat rash. Infants are prone to miliaria rubra because their eccrine sweat glands within the epidermis are not fully developed or have delayed patency. As a result, hot or humid environments lead to sweat accumulation within the glands and an inflammatory reaction.
Clinical manifestations include a fine (2-4 mm), erythematous, papular rash, as seen in this patient. It is typically located in intertriginous areas (eg, groin, axilla, anterior neck) or in areas where the skin is occluded (eg, back, head) by clothing, hats, or adhesive bandages. The rash is typically asymptomatic but may be pruritic, and infants are otherwise well appearing.
Management involves avoidance of overbundling and synthetic fabrics and switching to thin clothing made of breathable material (eg, cotton). Overheating and sweating can also be reduced by creating a cooler environment (eg, air conditioning, fan) when possible. If the rash is severe or associated with pruritus, topical low/mid-potency corticosteroids may be used as adjunctive therapy.
(Choice A) High-potency topical corticosteroids are not typically recommended in neonates due to the risk of systemic absorption enhanced by the thin stratum corneum in this age group. Moreover, absorption is further increased when applied to large, occluded areas, as is typically seen in miliaria rubra.
(Choice B) Topical antihistamines improve histamine-mediated pruritus, such as urticaria. In contrast to this patient's rash, urticaria presents with raised, erythematous wheals. Moreover, the inflammatory response in miliaria rubra is not histamine mediated.
(Choice C) Cutaneous candidiasis, which can be treated with topical nystatin, usually affects the intertriginous areas, not the back. Moreover, the rash is characterized by beefy-red plaques with satellite erythematous papules, which are absent in this patient.
(Choice E) Reassurance alone is appropriate for erythema toxicum neonatorum, which classically presents as a maculopapular rash that evolves into pustules on an erythematous base. This rash develops in the first 2-3 days of life and resolves by age 1 week, which is inconsistent with this patient's history.
Educational objective:
Miliaria rubra is a fine, erythematous, papular eruption that classically develops in infants exposed to hot or humid environments and affects the intertriginous areas or areas under occlusion. Management involves avoidance of overheating by use of thin, cotton clothing and placement in a cool environment when possible.