Delayed cutaneous manifestations following HFMD may be seen in the form of Beau’s lines, separation of nail plate from nail matrix (onychomadesis), and desquamation. The present study describes various delayed cutaneous findings of HFMD following an outbreak in Siliguri, West Bengal, India.

This descriptive follow-up study was carried out at Pediatrics Outpatient Department of the North Bengal Medical College, West Bengal, India, from July 2014 to December 2014. Clearance from Institutional Ethical Committee was taken. All children (age 6 months to 15 years) presenting with clinical features of HFMD were enrolled in the study. Those with recent history of any illness like streptococcal infection, measles, and Kawasaki disease and those with intake of drugs implicated in nail matrix arrest (e.g. cloxacillin, valproic acid, carbamazepine); or trauma to nails were excluded. Patients with atypical clinical presentation or with possibility of any other diagnoses were also excluded. Complement fixation test for a panel of antibodies against coxsackievirus A2, A4, A7, A9, A10, and A16 was performed for confirmation of diagnosis in some cases. Patients were advised to follow-up after a week and subsequently every 2 weeks for a period of 3 months. Detailed examination of the skin and nails was performed during the follow-up visits.

Out of 87 patients registered during the study period, 19 were lost to follow-up. Among the rest, 23 (12 males) developed delayed cutaneous findings. Details of initial presentations are given in Table I. Out of 11 patients who had serological work-up, 6 showed positive results for coxsackie virus A16 antibody. Nail changes included onychomadesis (19, 82.6%), discoloration (9, 39.1%), and Beau’s line (5, 21.7%) (Fig. 1 and Web Fig. 1). More than one finding was observed in 12 patients. Finger nails were more commonly involved than toe nails. Number of involved nails ranged from 3 to 20 (mean 13). Onychamadesis was most commonly observed in nails of middle finger (14, 73.7%), followed by thumb (12, 63.2%) and ring finger (10, 52.6%). The interval between appearance of rashes and onset of nail changes range from 17 to 46 (mean 32) days. Nail discoloration commonly involved middle finger (7, 77.8%), ring finger (5, 55.6%) and little finger (2, 22.2%). It was diffuse in nature, started proximally and slowly extended distally. In some cases, lateral nail plate was also involved. Recovery occurred by spontaneous re-growth of nails within 12 weeks, without any treatment.

TABLE I	Initial Presentation in Children With Hand Foot Mouth Disease

Fig. 1 (a) Onychomadesis, Beau’s line, and yellowish discoloration of finger nails; (b) Onychomadesis with loss of the right great toe nail and separation of nail plate from nail matrix and bed in the left great toe nail.

Desquamation limited to periungual and palmo-planter regions was noted in 7 patients (30.4%) after 2 weeks of follow-up. This subsided gradually in next 2-4 weeks following topical application of emollients.

Onychomadesis is a non-inflammatory condition characterized by proximal separation of nail plate from nail matrix with or without subsequent complete shedding of nails. Besides Coxsackievirus infection, it may also be seen in streptococcal infection, measles, Kawasaki disease, epidermolysis bullosa, periungual dermatitis, nail trauma, and some drugs.

In this study, nail abnormalities were evident in nearly one-third of the patients of HFMD on follow-up. We also observed nail discoloration in some patients which has not been described previously. Several reports [5,8-10] have described nail changes following HFMD since the temporal relation was first reported by Clementz, et al. [10]. The mechanism of nail changes still remains unexplained but it has been proposed that onychomadesis is caused by inflammation close to the nail matrix [12]. In the outbreak of HFMD in Finland in 2008, Osterback, et al. [13] detected Coxsackievirus A6 in shed nail fragments of a patient who had onychomadesis following a HFMD episode. The authors suggested that Coxsackievirus A6 replication damages the nail matrix, resulting in onychomadesis [12]. Nail abnormalities have only rarely been documented from previous HFMD outbreaks in India [5].

The present study had limitations of a hospital-based study, a high loss to follow-up, and lack of etiological work-up in majority of the cases. Moreover, we could not analyze any risk factor or possible mechanism of these findings.

We conclude that delayed cutaneous findings following HFMD are common. Parents should be counseled regarding possibility of these dermatological manifestations and their benign course.

Contributors: SSN: conception of the study, acquisition of data and drafting the manuscript; AD: design of the study, acquisition of data and revising the manuscript for important intellectual content; RKM: analysis and interpretation of data and revising the manuscript for important intellectual content. All the authors approved the final version of manuscript.

Funding: None; Competing interest: None stated.