Ans. is 'c' i.e., Streptococcal pyogenes Cellulitis is characterized by infection and inflammation of loose connective tissue, with limited involvement of the dermis and relative sparing of the epidermis. Streptococcus pyogenes and S. aureus are the most common etiologic agents. Children with relapsed nephrotic syndrome may develop cellulitis due to Escherichia coli. Cellulitis presents clinically as an area of edema, warmth, erythema, and tenderness. The lateral margins tend to be indistinct because the process is deep in the skin, primarily involving the subcutaneous tissues in addition to the dermis. Application of pressure may produce pitting. Although distinction cannot be made with ceainty in any paicular patient, cellulitis as a result of S. aureus tends to be more localized and may suppurate, whereas infections due to S. pyogenes (group A streptococcus) tend to spread more rapidly and may be associated with lymphangitis. MRSA is usually seen in hospitalised child.