ONYCHOMADESIS X POST VARICELLA

Onychomadesis Following Varicella Infection: Is it a Mere Co-incidence?

Indrashis Podder, Anupam Das, and Ramesh Chandra Gharami

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Sir,

Onychomadesis is separation of the nail plate from the nail matrix beginning at its proximal end, probably due to temporary arrest of the growth of the latter.[1] Viral infections, especially hand-foot-mouth disease (HFMD), have been recently nominated as a cause of this disorder. We however present here a case of onychomadesis following varicella infection (chicken pox).

A 7-year-old girl presented to our out-patient department (OPD), with painless discoloration of her right index finger nail, along with its separation at the proximal end for the last 4 days. There was no associated history of trauma. However, her medical records suggested that she had an uneventful recovery from an episode of chickenpox (Varicella infection) about 5 weeks ago. There was no history of any other illness in the past; family history and drug history were non-contributory. Dermatological examination of the right index finger revealed the separation of its nail plate from the nail bed, at the proximal end [Figure 1]. All other finger and toe nails were normal. No other cutaneous or mucosal lesion was noted except the presence of a few pock marks (post varicella) scattered mainly over her trunk; systemic examination was also within normal limits. The diagnosis of onychomadesis was made, and her parents were counselled regarding the benign nature of the disease.

Figure 1

Onychomadesis affecting the right index finger nail

Onychomadesis presents as painless,[2] spontaneous separation of the nail plate beginning at its proximal end. Temporary arrest of the function of the nail matrix may be the inciting factor. Subsequently, the whole nail plate may shed off, followed by the growth of a new nail plate. Although a small fraction of cases are idiopathic in nature,[3] there are several reported causes of onychomadesis, namely trauma,[2] neurologic disorders, peritoneal dialysis, cutaneous T-cell lymphoma, Kawasaki's disease, drug allergy, keratosis punctata Palmaris et plantaris,[1] pemphigus vulgaris[1,4] and bullous pemphigoid.[4] Some notable drugs which may lead to onychomadesis are antineoplastic agents, azithromycin and retinoids.[1] It can also occur in association with pyogenic granuloma and cast immobilization following fractures.[5] Some authors have even termed this condition familial.[6,7] Past history, drug history and family history were non-contributory in our case.

Recently, several workers have reported the occurrence of onychomadesis following a viral disorder called HFMD, caused mainly by Coxsackie virus.[2,7,8,9] It has also been reported following a fungal infection of the nail.[10] Kocak et al. (2013) reported a case of onychomadesis following varicella infection in two sisters.[11] In our case also onychomadesis developed following the healing of varicella infection, the first such report from India. The different causes of onychomadesis are tabulated below [Table 1].

Table 1

Different causes of onychomadesis

Although onychomadesis per se is a non-infective condition, the temporal association with these infections is utterly baffling in nature; however, some authors have stated that virally induced cytopathic damage of the nail matrix may be responsible for this condition.[7] The mean latency period between a viral infection (HFMD) and onychomadesis has been reported to be around 40 days;[14] in our case also, the latency period following another viral infection (varicella) has been found to corroborate to the reported data (about 35 days). However, there is still a raging debate whether this condition occurs as a co-incidence following viral infection or there is a definite mechanism which is yet to be elucidated. As there is only a single report of onychomadesis following varicella infection prior to this case, we cannot ascertain whether varicella infection may be regarded as an inciting factor.

This is one of the few reports of onychomadesis following varicella infection in the literature; more such reports are needed to ascertain whether this association is purely co-incidental or there is something more to what meets the eye.