Scott Walker, from Kansas in the US, shared the health warning with other parents in a bid to raise awareness on the dangers of 'hair torniquets' in small babies.
After trying to calm their 'cranky and screaming' daughter Molly, dad Scott and mum Jessica took off her socks and found the hair torniquet that was bothering their baby.
Scott wrote on Facebook: 'Had a small scare this afternoon with Ms. Molly. What happened was new to me, but apparently not totally uncommon, so I figured I'd share with my fellow parents out there.'
He continued: 'I was with the family over lunch and Molly was cranky and screaming--nothing out of the ordinary. As worked up as she was getting, she started to overheat, which prompted Jess to remove her socks and cool her down. That's when we saw her toe.'
After spotting the dangerous condition, Molly's mum, who's a nurse, removed the hair with tweezers and a magnifying glass. They took the picture they posted on Facebook about 45 minutes after, and Molly's toe is still visibly swollen.
'Unfortunately, the hair managed to cut all the way through Molly's skin, completely around her toe, but it could have been worse had it gone much longer untreated, or if the hair wasn't accessible', Scott wrote on his Facebook post, which has had over 10,000 shares.
Despite removing the dangerous hair strand, Scott and Jessica still took their daughter to the doctor, who told them to always check babies' toes in the future if they're inconsolable.
What is a 'hair torniquet' and why is it dangerous?This hard to spot condition happens when a small strand of hair wraps itself around a baby's toe so tight that it can cut off blood circulation, which can potentially lead to amputation.
The rare medical problem, known as 'toe tourniquet syndrome', can also affect other appendages like penises and ear lobes, causing inflammation and potentially infections.
Hair torniquets can be caused by the baby's hair, but mums suffering from post-pregnancy hair-loss are also advised to take special care and check mittens and clothes for loose strands of hair.
Because human hair is so thin, the condition can be very hard to spot, especially if it's caused by blond hair.
If your baby is in distress and you can't find out why, remember to check for hair torniquets in toes, ear lobes and penises if you have a boy.