Hello,
Thanks for posting your query .
Erythema nodosum and breathing difficulty in a child may often indicate significant underlying illnesses like sarcoidosis , tuberculosis , infections with strep or fungi , other inflammatory disorders , cardiovascular problems like aortic stenosis etc.
As such even a minor cause like nutritional anaemia ( low hemoglobin ) may be the cause of her easy fatigue and breathlessness which may occur in normal children in this age group due to picky eating habbits .
However since she has breathlessness even on routine activities like Running , playing or other such age appropriate activity then it's best to get her evaluated by her pediatrician for a confirmation of diagnosis .
The doctor after a thorough examination and tests like X-ray , complete blood count etc come to the exact cause and start appropriate treatment .
It's important not to neglect her symptoms as this might progress and the child might develop complications due to the low oxygenation of tissues . Even anaemia should be treated with nutritional iron supplements to help the child lead a healthy life.
Hope I have answered your query.
Kindly accept my answer if you have no further queries.
Wishing her good health.
Regards

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