A case of varicella complicated by cellulitis and scarlet fever due to Streptococcus pyogenes.

We report a 4-year-old boy with cellulitis and scarlet fever due to streptococcal infection following the onset of varicella. He developed a painful ulcer and subcutaneous induration on the left shoulder and a small, light-red-colored rash on the trunk at approximately the same time as the development of vesicles over the entire body. Streptococcus pyrogenes was isolated from samples from the posterior intranasal space and the ulcer on the shoulder. The clinical symptoms improved with the administration of antibiotics and intravenous drip infusion, but it took approximately one month from the first visit for the subcutaneous induration to disappear and the ulcer to heal with epithelialization. The complication of secondary streptococcal infection in varicella is relatively rare in Japan, but in Western countries there have been many reported cases of life-threatening necrotizing fasciitis and necrotizing pyomyositis due to secondary streptococcal infection following varicella. Close attention should be paid to streptococcal infection as a complicaion of varicella.