A 4-year-old boy is brought to the office due to a rash. Four days ago, the patient developed a localized rash consisting of a few small, round spots on his left foot. Over the next 2 days, some of the spots developed into pustules, and the affected area appeared slightly moist. The rash is mildly itchy and painful. His sister, with whom he shares a room, has also developed a few small, round spots on her hands. The patient has atopic dermatitis and intermittent asthma, for which he uses over-the-counter emollients and albuterol as needed, respectively. Vital signs are normal. Physical examination shows 5-7 small papules and pustules on the left dorsal foot. Some lesions are covered with a transparent, yellow crusting. There is no induration or streaking erythema. The rest of the examination is normal. Which of the following is the most appropriate next step in management of this patient?

Question

A 4-year-old boy is brought to the office due to a rash.  Four days ago, the patient developed a localized rash consisting of a few small, round spots on his left foot.  Over the next 2 days, some of the spots developed into pustules, and the affected area appeared slightly moist.  The rash is mildly itchy and painful.  His sister, with whom he shares a room, has also developed a few small, round spots on her hands.  The patient has atopic dermatitis and intermittent asthma, for which he uses over-the-counter emollients and albuterol as needed, respectively.  Vital signs are normal.  Physical examination shows 5-7 small papules and pustules on the left dorsal foot.  Some lesions are covered with a transparent, yellow crusting.  There is no induration or streaking erythema.  The rest of the examination is normal.  Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d6d5_1b29_bc81_57aa50874633_MD0003_00 This patient's yellow-crusted papules and pustules are consistent with nonbullous impetigo. Impetigo is a superficial skin infection most commonly caused by Staphylococcus aureus or group A Streptococcus (Streptococcus pyogenes). Predisposing factors include a warm and humid climate, poor hygiene, and preexisting skin trauma/inflammation (eg, scabies, atopic dermatitis). Nonbullous impetigo is most common, but some cases present with bullous impetigo (ie, flaccid bullae containing yellow fluid). Impetigo classically begins with papules and pustules on the face or extremities. The lesions may be painful or pruritic. Over the course of a week, the pustules rupture and harden into a characteristic golden-yellow (honey-colored) crusting. Local lymphadenopathy can be present, but fever is unusual. Antibiotics are indicated to reduce transmission (including autoinoculation to distant sites) and recovery time. Topical antibiotics (eg, mupirocin) are adequate for localized infection and preferred over oral antibiotics due to fewer adverse effects and decreased risk of antibiotic resistance. Oral antibiotics are warranted for widespread nonbullous impetigo, which makes topical therapy impractical. Cephalexin and dicloxacillin are possible options; amoxicillin is not recommended due to its limited activity against S aureus (Choice B). Bullous impetigo also requires oral antibiotic therapy. Impetigo is contagious, making hand hygiene and coverage of actively draining lesions also important to prevent spread. (Choice A) Oral acyclovir is used to treat herpes simplex virus infection, which typically causes painful clusters of vesicles on an erythematous base. Pustules with yellow crusting make this diagnosis unlikely. herpes simplex virus infection (Choice C) Topical corticosteroids (eg, hydrocortisone) treat atopic dermatitis, which causes erythematous, dry, thickened skin in flexural areas (eg, antecubital and popliteal fossae). Although this patient has atopic dermatitis, the presence of pustules indicates a bacterial infection. (Choice D) Topical ketoconazole treats tinea corporis (ringworm). In contrast to this patient, ringworm causes an enlarging, annular plaque with a raised border. (Choice F) Scabies is treated with topical permethrin; symptoms include markedly pruritic, small papules classically located between the fingers and toes, in the axillae, and along the waistline. This patient's isolated rash and mild pruritis make scabies unlikely. Scabies Educational objective: Nonbullous impetigo is characterized by papules and pustules with overlying honey-colored crusting. Topical antibiotics (eg, mupirocin) are the treatment of choice for localized infection. References: Impetigo. (http://www.ncbi.nlm.nih.gov/pubmed/28613693) Impetigo: diagnosis and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/25250996)

A 4-Year-Old Boy Is Brought to the Office Due to a Rash