Secondary infection of preaxial polydactyly following varicella infection.

Sir,

Varicella or chickenpox infection is caused by varicella-zoster virus and usually has benign, contagious course with characteristic exanthematous, vesiculobullous lesions mostly in childhood.[1] Secondary bacterial infections of skin and soft tissues are most common complications of chickenpox and may range from 2% to 5% of all cases.[2] Musculoskeletal complications are rare but at times morbid as mostly lead to acute osteomyelitis and septic arthritis. Only five cases were complicated to osteomyelitis in two studies with cumulative pool of 297 cases of German and Turkish region.[34] Other notable musculoskeletal complications are necrotizing fasciitis, deep tissue abscess, toxic shock syndromes, multifocal arthritis, pyomyositis, and necrotizing pyomyositis.[56]

A 6-year-old male child was brought to us alongside parents with painful, swollen right extra thumb (preaxial polydactyly). No regional- or systemic-associated anomaly was noted, and the symptoms of the extra digit were preceded by chickenpox infection a week earlier. There was the presence of characteristic rash of chickenpox at different stages of evolution in extremities and trunk. There was also a rash present over the swollen extra digit [Figure 1a]. The extra digit showed purulent collection at its base the next day [Figure 1b]. The deformity of the thumb was congenital and solitary. The anomalous digit was connected to the thenar region with a thin soft tissue stalk and was sensate but nonfunctional. Severe throbbing pain due to secondary infection, swollen nonfunctional digit, and possibility of complicating into the ischemic necrosis were reasons for opting the amputation of the digit and the surgery was done following parental consent [Figure 2]. No local immediate or remote complication was noted in postoperative period till the follow-up of 7 months.

Figure 1

The image of affected extra digit (preaxial polydactyly) with inflammation. The presence of typical varicella rash over the affected digit (a) and the suppuration near base of digit the following day (b)

Figure 2

Clinical image following removal of the digit and healing of the localized infection

Musculoskeletal complications of varicella require prompt recognition, diagnosis, and treatment as some of them may prove life- or limb-threatening. Secondary skin and soft tissue infections and cases of osteomyelitis are also reported.[7] Group A streptococcal infection predominates musculoskeletal cases and its profile is aggravating with time.[8] The culture of postamputated digit and pus was negative in our case. The advance investigations could not be done due to financial issues. In our case, associated vasculopathy, a well-described complication, may have led to the aforementioned secondary infection or both as a small stalk was connecting the digit with thenar region. Both primary infection and reactivation of infection can cause vasculopathies and may lead to tissue infarction in uni- or multifocal manner. Coagulopathy-related disorders were noted in cases with purpura fulminans as postvaricella complications with immune-related protein S deficiency leading to disseminated intravascular coagulation.[9] Associated vasculitis or thrombosis are other causes of thrombotic events postvaricella infection and may lead to limb amputation.[10] A cautious approach is warranted in dealing with cases of varicella infection, and knowledge of rarer complications is beneficial.

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