Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for severe difficulty breathing, fainting, a new seizure, sudden confusion, or other immediately life-threatening symptoms.
These are not typical features of pure cutaneous histiocytosis, but they require emergency care whatever the cause.
And for anyone, someone who:
If you already have a diagnosis, contact your usual clinical team promptly if lesions are growing quickly, becoming painful, opening, or producing discharge.
New swollen glands, persistent fever, unexplained weight loss, bone pain, unusual thirst or urination, or breathing symptoms also need assessment.
Seek urgent medical care for a rapidly worsening skin infection, particularly spreading redness with fever, increasing warmth, pus, or severe pain.
And for anyone, someone who:
Arrange a routine appointment if you develop unexplained bumps, plaques, or nodules that persist, multiply, or change.
A skin examination is especially appropriate if a lesion repeatedly crusts, bleeds, or fails to heal.
Every sign above is quoted from the sofidex article on Pure cutaneous histiocytosis. If you are not sure, err upward — it is always reasonable to be checked.