Letters
Musculoskeletal diseases Child health Toxicology
Volume 199 - Issue 5

Paediatric osteomyelitis after exposure to toxic Ochrogaster lunifer moth

Authors:  John J van Bockxmeer and Jennifer Green

Med J Aust 2013; 199 (5): 331-332. || doi: 10.5694/mja13.10077
Published online: 2 September 2013
A young boy’s painful encounter with a moth playing possum.
Download PDF (130 KB)
Share: Share on Blue Sky Share on Facebook Share on LinkedIn Share by email

To the Editor: We wish to alert our colleagues to an unusual case of culture-negative paediatric osteomyelitis after exposure to a toxic Australian moth. A previously well 5-year-old boy presented to a remote hospital emergency department with inflammation and urticarial rash of the left third finger and left fifth toe after playing with a “dead” moth. His mother had removed numerous small filaments at the time, and he had no other significant history, exposure to toxins, or trauma.

The inflammation failed to abate despite multiple courses of antibiotics, antihistamines and steroids. Twenty-one days after exposure, his toe was grossly swollen, tender and erythematous, with a bloody exudate. Results of biochemical and haematological investigations were normal, and an x-ray demonstrated changes consistent with osteomyelitis. The toe was debrided, and chronic inflammatory tissue with destruction of tendon and bone was found. A foreign body and middle phalanx were removed. Histopathological analysis of the bone fragment demonstrated a neutrophilic exudate with new bone formation and associated granulation tissue consistent with acute on chronic osteomyelitis. The patient completed 12 weeks of oral ciprofloxacin treatment, and the toe completely healed with return to normal function.

Although the moth the boy had played with was not available for identification, the boy’s mother provided photographs of subsequently observed specimens. Using these images, entomologists at the Western Australian Museum identified the moth as the Ochrogaster lunifer species (Box),1 and it was assumed to be the causative agent. This moth is a pale colour with a variable appearance and is widely distributed throughout Australia. The processionary caterpillars have been associated with outbreaks of paediatric dermatitis, conjunctivitis and respiratory illness.2,3

O. lunifer moths have barbed, hairy filaments (setae) that are known to cause an urticarial rash, corneal inflammation and facial oedema.4 The moths envenomate after contact with an irritant produced by a gland at the base of setae on their feet.2 When agitated, they appear to be dead by curling their abdomen and lying immobilised on one side, making them a target of children’s attention. Moth avoidance protocols have been published to try to reduce moth urticaria.5

O. lunifer is an underrecognised hazard to Australian communities. Physical variability and an unknown aetiology make moth urticaria a diagnostic and management dilemma. Caterpillars and moths can cause inflammatory digital swelling in children, so particular care is needed to ensure all filaments are removed. In patients who do not respond to conventional antibiotics and antihistamines, early surgical evacuation of filaments may be required to prevent progression to osteomyelitis.

North-western Australian Ochrogaster lunifer*

* Specimen collected by McCaffrey and Gibson in the Pilbara region of Western Australia, 2006.1 Image used with permission under the terms of the Creative Commons Attribution 3.0 Australia license.

Authors

  • John J van Bockxmeer1
  • Jennifer Green2
  • 1. Emergency Department, Sir Charles Gairdner Hospital, Perth, WA.
  • 2. Princess Margaret Hospital, Perth, WA.

Correspondence: john.vanbockxmeer@health.wa.gov.au

Competing interests

No relevant disclosures.

Acknowledgements

We acknowledge the CSIRO (Commonwealth Scientific and Industrial Research Organisation) and the Western Australian Museum for assistance with identifying the moth.

References

View this article on Wiley Online Library