Neonatal cellulitis (seen in infants younger than age 3 months) is an uncommon inflammatory bacterial infection of deep dermis and subcutaneous tissues often caused by group B Streptococcus (GBS).

In cellulitis, bacteria invade through small cracks, fissures, or breaks in the skin. The clinical manifestations include rapidly progressive areas of skin edema, erythema, heat, and pain with or without associated lymphangitis or adenopathy. In this age group, risk factors for GBS should be considered, which include maternal GBS colonization, mode of delivery, episiotomy, prematurity, hospitalization, and prior antibiotic treatment.

It is unlikely for infants aged younger than 60 days who have skin and soft tissue infections (SSTIs) to develop sequela such as bacterial meningitis, osteomyelitis, or urinary tract infections (UTIs). However, bacteremia may be seen in up to 1%-2% of infant patients with SSTIs; this rate can be much higher in febrile infants with cellulitis.

GBS Cellulitis-Adenitis Syndrome: This is a rare, late-onset infection with GBS that presents with cellulitis and lymphadenitis, cellulitis alone, or more rarely, with lymphadenitis alone. It most often presents with accompanying bacteremia and sometimes meningitis. The cellulitis most often occurs on the head and neck (particularly the submandibular area), followed by the inguinal region. This infection often occurs in male infants and in infants who were born prematurely and with a low birth weight. Clinical manifestations include irritability, fever, enlarged lymph nodes, and cutaneous signs of cellulitis (such as erythema and swelling).

Related topics: orbital cellulitis, preseptal cellulitis