A 4-month-old girl is brought to the clinic by her parents for a well-child check. She was evaluated 2 weeks ago for a rash in the diaper area. At that visit, the patient was found to have erythematous papules in the diaper area that spared the skin folds. Her symptoms improved with use of a petrolatum barrier ointment with every diaper change. Today, vital signs and physical examination are normal. Which of the following most likely contributed to this patient's prior skin findings?

Question

A 4-month-old girl is brought to the clinic by her parents for a well-child check.  She was evaluated 2 weeks ago for a rash in the diaper area.  At that visit, the patient was found to have erythematous papules in the diaper area that spared the skin folds.  Her symptoms improved with use of a petrolatum barrier ointment with every diaper change.  Today, vital signs and physical examination are normal.  Which of the following most likely contributed to this patient's prior skin findings?

Quizplus · Accepted Answer

11ec160b_3aa9_a419_9249_6dc5b994efb3_MD0001_00 This patient's rash that resolved with use of a barrier ointment was likely irritant contact diaper dermatitis, the most common diaper rash in infants. Characteristic features include erythematous papules confined within the diaper area. In contrast to candidal diaper dermatitis, another common diaper rash caused by a secondary yeast infection, irritant contact diaper dermatitis does not have skinfold involvement or satellite lesions (ie, discrete lesions beyond the borders of the main rash). Irritant contact diaper dermatitis is predominantly caused by skin barrier breakdown from exposure to urine and stool trapped within the diaper. Patients with frequent stooling (eg, diarrhea) are at increased risk because urease produced by fecal bacteria causes an increase in local skin pH, which allows for activation of proteolytic enzymes that disrupt the stratum corneum. Areas of macerated skin are then prone to frictional damage from the diaper, which further exacerbates the rash. The treatment for irritant contact diaper dermatitis is a thick barrier ointment (eg, petrolatum) or paste (eg, zinc oxide), which provides the skin an adherent layer of protection from contact with the stool and urine. Other measures to reduce irritant exposure include frequent diaper changes and diaper-free periods. (Choice A) Abnormal keratin expression describes the pathogenesis of psoriasis, which manifests as erythematous, scaly plaques. Psoriasis rarely presents in the diaper area and is usually chronic and persistent without topical corticosteroid treatment. (Choice C) Increased hapten sensitization describes allergic contact dermatitis, which is uncommon in the diaper area but can occur with an allergy to a component (eg, dye, fragrance) in diapers or wipes. The rash is unlikely to resolve without complete removal of the offending antigen (eg, changing diaper brand), and topical corticosteroids are also required in many cases. (Choice D) Local bacterial colonization with Staphylococcus or Streptococcus leads to impetigo in the diaper area. Honey-crusted pustules are classic, and topical antibiotics are the first-line treatment. (Choice E) Scabies is a mite infestation that causes itchy, erythematous papules. The rash can involve the diaper area, but lesions would also be expected elsewhere (eg, axillae, hands, feet). Treatment is with permethrin, and resolution would not be expected with petrolatum alone. Educational objective: Irritant contact diaper dermatitis is the most common diaper rash and is characterized by skin barrier breakdown as a result of exposure to fecal bacteria that causes increased local skin pH. Treatment is with a barrier ointment that prevents skin contact with urine and stool.

A 4-Month-Old Girl Is Brought to the Clinic by Her