Sir,
Hand, foot and mouth disease (HFMD) is a common viral illness affecting children, presenting with fever, malaise, vesicular lesions in the mouth and maculo-papular or vesicular lesions on the hands, feet and buttocks. The symptoms usually resolve without major complications in about 1-3 weeks. It is usually seen from July to October in India. Recently, HFMD has been reaching epidemic proportions with outbreaks being reported from various parts of India including Shimla, West Bengal and parts of southern and eastern India.[123] The causative organisms of HFMD are Coxsackie virus A 16, 4, 5, 6, 7, 9, 10 and 24, Coxsackie B virus 1, 2, 3, 4, 5, Enterovirus 71 and Echoviruses.[4] In a study conducted in southern and eastern India, Coxsackie virus A16 and A6 were identified as major causative organisms of HFMD.[2] Onychomadesis or nail shedding is a rare complication of HFMD, which can be a major cause of parental anxiety if the etiology cannot be explained. Reports of onychomadesis following HFMD are few from India and may have been missed out due to lack of awareness among clinicians.
A 2-year-old boy from Bangalore presented with HFMD and recovered 1-week after onset of illness with no complications. Six weeks later, he developed Beau's lines (transverse ridging of the nail plate) on all finger and toe nails and 10 days later the nails started falling off [Figures 1 and 2]. There was no history of preceding nail trauma, injury or drug intake. His height and weight were normal for age, and there was no other significant illness in the past. He was fully immunized and belonged to the higher socioeconomic group. There was spontaneous re-growth of the nails in a month.
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Figure 1: Beau's lines on the ring and little finger, onychomadesis on the middle finger and new nail formation on the index finger
Figure 2: Onychomadesis of the toe nails
Onychomadesis is an acute noninflammatory condition affecting the nail matrix which results in spontaneous separation of the nail plate from the matrix starting at the proximal end. In healthy children, onychomadesis is a rare finding and can be a cause for anxiety in parents. Onychomadesis as a rare and late complication of HFMD was first described in the year 2000 in USA and later in Finland, Taiwan, Japan and Spain.[56] Patients present with clinical manifestations ranging from Beau's lines due to slowing of nail matrix growth or onychomadesis due to complete arrest of nail matrix growth about 1-2 months after the initial symptoms of HFMD. This is usually followed by a spontaneous re-growth of nails in 1-4 months. Coxsackie virus A6, A10 and B1 have been commonly associated with onychomadesis following HFMD. The mechanism by which the nail matrix is affected in HFMD is unknown, but replication of the virus causing temporary damage to the nail matrix has been considered to be the most plausible explanation.[7] In an outbreak in Spain in 2008, infection with an Enterovirus serotype causing HFMD plus co infection with Coxsackie virus B1 has been hypothesized as a cause for onychomadesis. Genetic and environmental susceptibility, familial predisposition, history of previous HFMD, age <2 years have also been postulated as potential causes for onychomadesis. Our child had just completed 2 years and had no previous history of HFMD. His other two siblings had no history of prior HFMD or onychomadesis. Other causes of onychomadesis in children include trauma, poor nutrition, severe illness, auto immune diseases, drugs like sodium valproate and chemotherapeutic agents and idiopathic causes.
Clinicians should be aware of this rare but benign complication of HFMD, which resolves spontaneously without intervention. As onychomadesis is a late complication of HFMD, there would not be any evidence of HFMD at the time the child has onychomadesis. History suggestive of preceding HFMD, should be taken in any child who presents with onychomadesis. Parents should be counseled accordingly. Further large scale studies are needed in India to determine the incidence of onychomadesis following HFMD. The causative viruses behind this new complication of HFMD and the other predisposing factors for developing this complication in India also need to be studied.
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Conflicts of Interest
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