Tackling Inflammatory and Infectious Nail Disorders in Children
Nail disorders are common in the pediatric population and affect quality of life. We review inflammatory conditions (ie, nail psoriasis, nail lichen planus [NLP], trachyonychia, nail lichen striatus, nail atopic dermatitis [AD]) as well as infectious conditions (ie, nail disease due to hand, foot, and mouth disease [HFMD] or Kawasaki disease, onychomycosis, acute paronychia). Inflammatory and infectious nail conditions may involve the skin or occur in isolation. By highlighting the distinctive features and clinical presentations of these infectious and inflammatory nail disorders in children, we aim to raise awareness among dermatologists to improve diagnosis and management.
Practice Points
- Nail plate pitting is the most common clinical sign of nail psoriasis in children.
- Nail changes are common in hand, foot, and mouth disease, with the most frequent being onychomadesis.
- Because onychomycosis may resemble other nail disorders, mycologic confirmation is recommended to avoid misdiagnosis.
- Many nail conditions in children self-resolve but recognizing these manifestations is important in providing anticipatory guidance to patients and caregivers.
FUNGAL INFECTIONS
Onychomycosis
Onychomycosis is a fungal infection of the nails that occurs in 0.2% to 5.5% of pediatric patients, and its prevalence may be increasing, which may be due to environmental factors or increased rates of diabetes mellitus and obesity in the pediatric population.47 Onychomycosis represents 15.5% of nail dystrophies in pediatric patients.48 Some dermatologists treat presumptive onychomycosis without confirmation; however, we do not recommend that approach. Because the differential is broad and the duration of treatment is long, mycologic examination (potassium hydroxide preparation, fungal culture, polymerase chain reaction, and/or histopathology) should be obtained to confirm onychomycosis prior to initiation of antifungal management. Family members of affected individuals should be evaluated and treated, if indicated, for onychomycosis and tinea pedis, as household transmission is common.
Currently, there are 2 topical FDA-approved treatments for pediatric onychomycosis in children 6 years and older (Table 2).49,50 There is a discussion of the need for confirmatory testing for onychomycosis in children, particularly when systemic treatment is prescribed. In a retrospective review of 269 pediatric patients with onychomycosis prescribed terbinafine, 53.5% (n=144) underwent laboratory monitoring of liver function and complete blood cell counts, and 12.5% had grade 1 laboratory abnormalities either prior to (12/144 [8.3%]) or during (6/144 [4.2%]) therapy.51 Baseline transaminase monitoring is recommended, though subsequent routine laboratory monitoring in healthy children may have limited utility with associated increased costs, incidental findings, and patient discomfort and likely is not needed.51
Pediatric onychomycosis responds better to topical therapy than adult disease, and pediatric patients do not always require systemic treatment.52 Ciclopirox is not FDA approved for the treatment of pediatric onychomycosis, but in a 32-week clinical trial of ciclopirox lacquer 8% use in 40 patients, 77% (27/35) of treated patients achieved mycologic cure. Overall, 71% of treated patients (25/35) vs 22% (2/9) of controls achieved efficacy (defined as investigator global assessment score of 2 or lower).52 In an open-label, single-arm clinical trial assessing tavaborole solution 5% applied once daily for 48 weeks for the treatment of toenail onychomycosis in pediatric patients (aged 6–17 years), 36.2% (20/55) of patients achieved mycologic cure, and 8.5% (5/55) achieved complete cure at week 52 with mild or minimal adverse effects.53 In an open-label, phase 4 study of the safety and efficacy of efinaconazole solution 10% applied once daily for 48 weeks in pediatric patients (aged 6 to 16 years) (n=60), 65% (35/60) achieved mycologic cure, 42% (25/60) achieved clinical cure, and 40% (24/60) achieved complete cure at 52 weeks. The most common adverse effects of efinaconazole were local and included ingrown toenail (1/60), application-site dermatitis (1/60), application-site vesicles (1/60), and application-site pain (1/60).54
In a systematic review of systemic antifungals for onychomycosis in 151 pediatric patients, itraconazole, fluconazole, griseofulvin, and terbinafine resulted in complete cure rates similar to those of the adult population, with excellent safety profiles.55 Depending on the situation, initiation of treatment with topical medications followed by addition of systemic antifungal agents only if needed may be an appropriate course of action.
BACTERIAL INFECTIONS
Acute Paronychia
Acute paronychia is a nail-fold infection that develops after the protective nail barrier has been compromised.56 In children, thumb-sucking, nail-biting, frequent oral manipulation of the digits, and poor skin hygiene are risk factors. Acute paronychia also may develop in association with congenital malalignment of the great toenails.57
Clinical manifestations include localized pain, erythema, and nail fold edema (Figure 4). Purulent material and abscess formation may ensue. Staphylococcus aureus as well as methicillin-resistant S aureus and Streptococcus pyogenes are classically the most common causes of acute paronychia. Treatment of paronychia is based on severity. In mild cases, warm soaks with topical antibiotics are indicated. Oral antibiotics should be prescribed for more severe presentations. If there is no improvement after 48 hours, surgical drainage is required to facilitate healing.56
FINAL THOUGHTS
Inflammatory and infectious nail disorders in children are relatively common and may impact the physical and emotional well-being of young patients. By understanding the distinctive features of these nail disorders in pediatric patients, dermatologists can provide anticipatory guidance and informed treatment options to children and their parents. Further research is needed to expand our understanding of pediatric nail disorders and create targeted therapeutic interventions, particularly for NLP and psoriasis.
