Fellow frequent symptom checkers will understand how frustrating it can be trying to work out what your rash is and how it can affect you.
After all, there are tonnes and tonnes of conditions that can lead to red, itchy, or bumpy skin – and while many are completely harmless, it’s still a good idea to check your symptoms with a pro if you’re worried.
Especially, as if turns out, if you have one particular type of heat rash.
Dr. Karan Raj recently posted a TikTok responding to a young woman whose stomach had been affected by ‘erythema ab igne’, explaining that you “should be worried” if you see it on yourself or someone else.
Here’s the clip:
What causes the condition?
Erythema ab igne is Latin for ‘redness from fire’. So it makes sense that the rash comes from repeated exposure to heat, like through using a hot water bottle on your period or by using heat pads.
You won’t get the rash from a one-off hot water bottle sesh – as Dr. Raj says, the condition arises from “chronic” use of heat.
The rash more frequently affects bakers, metal workers, and other people exposed to an open flame for long periods of time – but increasingly, the condition has been spotted in those with heated car seats and people who spend a lot of time working on an overheated laptop (yikes).
OK, so what are the symptoms?
Well, the developed rash has a very distinctive appearance.
The American Osteopathic College of Dermatology (AOCD) describes it as a “reticulated, or fishnet-like, pattern of hyperpigmentation.“
But there are early warning signs you can heed before your spot the larger rash.
“Initially, lesions start as mottling or mildly pink patches and progress to the classic reddish or violaceous to (a) brown reticulated pattern,” the AOCD says.
And it can be accompanied by itching or burning sensations too – though this doesn’t always happen.
The rash can look a lot like livedo reticularis, which is associated with underlying conditions like lupus – so make sure you consult a pro if you spot a rash like this woman’s.
So, how can this rash hurt me?
It might not – but you should still get it checked.
The National Library of Medicine says that “While the rash is most often benign, its presence can indicate chronic inflammation or, less commonly, systemic illness and should prompt further investigation.”
They add that its presence could even signal “pre-malignant transformation”, for which you need a biopsy.
But even if it’s not caused by a chronic condition, catching sight of the rash should still cause you to visit your doctor.
As Dr. Raj says, if you need to use a hot water bottle often enough that it causes erythema ab igne, there’s a chance you could have deeper issues that need to be addressed by a doctor.
He says that if your pain is so bad you constantly need to use a hot water bottle, then you could have “endometriosis or a number of chronic gynaecological conditions, or bowel-related issues.”
“And if your doctor fobs you off,” he says, “you need to see another one until someone does something.”