Streptococcus pyogenes (S. pyogenes, group A beta-hemolytic-streptococcus) is a well-recognized pathogen for skin infections such as impetigo, cellulitis, erysipelas, ecthyma, and a trigger for conditions such as guttate psoriasis and atopic dermatitis. Mild cutaneous streptococcal disease can serve as a source for toxic shock syndrome. Less recognized is its uncommon role in cervical intertrigo, typically in the short-neck-length, chubby infant. Streptococcal intertrigo typically appears as a fiery-red, well-demarcated, moist rash most often located in the skin folds adjacent to the cervical area. It is usually mistaken for Candida intertrigo and treated for that condition. A rapid antigen detection test for group A streptococcus in a swab specimen of the surface of the intensely red intertriginous skin, paired with an overnight culture of a second swab of the skin surface, can diagnose the condition and facilitate initiation of appropriate local and systemic antistreptococcal therapy. To remind the primary care physician of this little-recognized entity, we report a case of cervical, inguinal and retroauricular crease streptococcal intertrigo in a 5-month-old boy.
A 5-month-old male infant with a history of mild-to-moderate atopic dermatitis was taken to his pediatrician’s office because of a worsening, “weepy rash” on the neck of 2 days’ duration. The beefy-red rash was visible in the cervical skin folds, left popliteal crease and right posterior auricular crease. There was also scattered mild atopic dermatitis. A complete physical examination was otherwise normal. Intertrigo, secondary to copious drooling into the neck folds, was believed to be the most likely diagnosis, and a 7- to 10-day course of mycostatin topical powder was prescribed.
Six days later, the baby was brought to the pediatrician’s office again because of a worsening rash. The diagnosis was changed to primary dermatitis with probable bacterial superinfection. A culture of the skin surface was obtained, and treatment was prescribed with cephalexin suspension (30 mg/kg/d in 3 divided doses) and dexamethasone suspension (2 mg every other day for 3 doses) to decrease the intensely inflamed skin. An overnight skin surface culture on 5% sheep blood agar yielded a heavy and almost pure growth of S. pyogenes, and the mother was asked to return promptly to the pediatrician’s office. A photograph was taken of the fiery-red, macerated moist intertriginous rash (Fig. 1). Three weeks later, the intense inflammation had largely subsided, but there was severe generalized atopic dermatitis that had not responded to topical corticosteroid creams or modification of the child’s diet.
Infants and toddlers are predisposed to cervical intertrigo for a number of reasons. Their necks are relatively short; some infants are also chubby, and their necks have deep folds. When an infant drools, saliva drains into the neck folds, creating a moist environment. The normal skin barrier can be breached, leading to superinfection with Candida or other organisms. Moreover, during winter and early spring, susceptible babies may be exposed to S. pyogenes after contact with infected older children or adults. Intertrigo should quickly respond to reduction of moisture, which can be accomplished by blowing a hair drier (on the “warm” setting) over the affected area and applying an absorptive baby powder after gentle cleaning and drying, and application of an antifungal topical cream such as mycostatin or ketoconazole.
Intertrigo is defined as a friction inflammation of closely approximated, moist skin folds. The most common microbiologic cause is Candida albicans. Staphylococcus aureus can also be isolated. Clinicians should consider S. pyogenes when examining an infant with a fiery-red, well-demarcated, moist intertriginous eruption. Honig et al1 describe 3 babies with foul-smelling cervical-fold intertrigo. It is reasonable to obtain several surface swab specimens for Gram stain, streptococcal rapid antigen test and overnight incubation of the specimen. Candida intertrigo is much more common than streptococcal intertrigo. However, the location of the strikingly homogeneous, fiery-red, well-demarcated, moist, foul-smelling, satellite-free rash in the neck folds and less commonly in the inguinal, popliteal or posterior auricular folds, and the poor clinical response to topical antifungal cream after a few days are clues that suggest consideration of S. pyogenes intertrigo.
Our search of the medical literature revealed 2 original publications reporting a total of 4 children with streptococcal intertrigo.1,2 Honig et al1 reported 3 infants, who were all <6 months of age. All 3 infants had fiery-red, foul-smelling intertrigo of the neck creases. A 3-month old with axillary fold streptococcal intertrigo was reported by Italian dermatologists in a Letter to the Editor of Pediatric Dermatology. 2
The 4 cases of streptococcal intertrigo that we were able to locate were in infants <6 months. Four of the 5 cases, including our patient, had intense involvement of the neck creases. Streptococcal intertrigo should be suspected in an infant who has intense, fiery-red, moist dermatitis of the neck or antecubital, popliteal or inguinal area. Our child’s study was also interesting because the streptococcal infection greatly exacerbated the atopic dermatitis.
1. Honig PJ, Frieden IJ, Kim HJ, et al. Streptococcal intertrigo
: an underrecognized condition in children. Pediatrics. 2003;112(6 pt 1):1427–1429
2. Neri I, Savoia F, Giacomini F, et al. Streptococcal intertrigo
. Pediatr Dermatol. 2007;24:577–578