Mystery of the painful leg lumps and an extremely rare infection

A young lady came into the surgery last week with some painful lumps on her shins.

She was quite baffled as to why these red bumps a couple of inches wide had appeared under the skin.

Not half as baffled as when I asked her if she’d had a cough a couple of weeks ago, though.

What’s the link between the two, then?

The painful lumps on her shin looked to me like something I’ve seen only a couple of times in my career, called erythema nodosum.

This is when there’s an inflammation of the layer of fat under the skin, most commonly in the shins but occasionally elsewhere like the thighs.

In half of all cases the cause remains elusive, despite our best efforts.

But for the other half, erythema nodosum happens due to a collection of conditions which seem to cause the immune system to go into overdrive and cause the lumpy shins.

It can be down to tuberculosis, the bacterial infection which affects the lungs. It may also be due to certain bacterial infections which cause diarrhoea.

It can also be triggered by sarcoidosis, chlamydia, certain inflammatory bowel conditions, medicines, or pregnancy.

Interestingly, it could also be a bacterial throat infection we know as strep throat.

You may have noticed that very few of those conditions mentioned have much if anything to do with your shins. Your skin is odd like that. It helps to question someone who comes in with the symptoms of erythema nodosum, as it might point to something else which requires treatment.

For instance, the woman who came to see me was in her twenties. This is the most common age range and gender to be affected by erythema nodosum.

It was likely her being on the combined pill is what sparked the condition. I therefore recommended she switched to a different type of birth control as a precaution.

As for the painful nodules themselves, they tend to clear up on their own after a few weeks.

Often they don’t need treatment, but ibuprofen can help with the inflammation, and supportive stockings apparently can help too.

It can recur but if it does, it’s worth mentioning to your GP again.