Fungal skin infections in children: A diagnosis to keep in mind

Fungal skin infections in children are increasingly prevalent, in particular in the immunocompromised. In these cases, knowledge of risk factors, including the presence of pets in the household, can make the difference in arriving at the right diagnosis.

In her lecture on paediatric dermatologic emergencies, Prof. A. Yasmine Kirkorian (George Washington University School of Medicine, Washington DC , USA) presented cases of unusual fungal infections [1]. Although mucormycosis is rare, cases are increasingly being recognised in immunocompromised patients due to increased awareness. The disease is associated with high morbidity and mortality [2]. The rhinocerebral, pulmonary, and disseminated forms are usually seen in patients with underlying haematological malignancies, such as leukaemia or lymphoma, in patients receiving immunosuppressive therapy or corticosteroids, and in patients with diabetes. Mucormycosis tends to lead to angioinvasion, which may lead to progressive dissemination.

Data on this topic is lacking in the literature. However, a recent retrospective study identified 12 cases of disseminated mucormycosis in immunocompromised children [3]. In this population-based study, 5 patients (42%) were salvaged through combined liposomal amphotericin/triazole treatment and extensive surgical interventions.

Prof. Kirkorian also presented the case of a 5-year-old infant with stage 3 Wilms’ tumour (nephroblastoma). The patient had previously been treated with chemotherapy and presented to the emergency room with neutropenic fever. On admission, red macules “the size of petechiae” were noted on the skin. Three days later, dermatology was consulted because the macule had turned into a large necrotic skin lesion. Finally, the organism Cunninghamella could be identified in a culture of the brain abscess. Infected skin tissue has to be excised immediately, and broad antifungals were applied.

In India, SARS-CoV-2 infections led to a splurge of rhino-orbital mucormycosis cases. In a retrospective study of 31 patients, SARS-CoV-2 positivity with concomitant steroid use was identified as the second most frequent risk factor (the most important was diabetes) in 61% of cases. All children were treated with intravenous liposomal amphotericin B and debridement of local necrotic tissue; only 3 of them died [4].

 

Guinea pigs: Not as harmless as they look

Much more frequent, and fortunately much less deadly, are dermal infections caused by Trichophyton [1]. Prof. Kirkorian presented the case of a 7-year-old girl that was taken to the emergency room with a worsening, oozing, bleeding alopecic plaque on the scalp. The girl recently got a guinea pig and had a lesion of tinea faciei. A microbiological examination of the skin revealed Trichophyton benhamiae. Prof. Kirkorian said that in these cases, inquiries about pets in the household are most important for a correct diagnosis: Children who show intense inflammatory manifestations on the face should be asked whether a guinea pig lives in the house. Mycological dermatophytosis primarily manifests on the eye and chin and is often caused by cuddling guinea pigs.

The underlying pathogen Trichophyton benhamiae was first described in Japan in 1998. Initially, such infections were misinterpreted as T. mentagrophytes or Microsporum canis infections. The reservoir of the pathogen is mainly guinea pigs but also other small rodents such as hamsters. The guinea pigs are usually completely symptom-free. Trichophyton benhamiae infections spread in Europe mainly through the importation of guinea pigs from Asia and are now more common than Microsporum canis infections. Superficial fungal examination and tissue examination may be negative with brisk inflammation.

When there is a high index of suspicion and a history of contact with a guinea pig, treatment should be performed empirically: terbinafine is the first drug of choice.

 

1. 
   
   1. Kirkorian AY, et al. Rash decisions: diagnosis and management of pediatric dermatologic emergencies. S046, AAD 2022 Annual Meeting, 25–29 March, Boston, MA, USA.
   2. Däbritz J, et al. Mycoses 2011;54:e785–788.
   3. Elitzur S, et al. J Fungi (Basel) 2021;7:165.
   4. Ravani SA, et al. Indian J Ophthalmol 2021;69:1563–1568.

 

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Posted on 17 May, 202223 May, 2022