Tiny socks may finish off a baby's outfit, but specialists have identified a new condition on infants' legs which can be caused by tight elastic bands.
This baby developed sock-line bands at just one week
"Sock-line bands" are raised, reddish markings around the ankle or leg which can develop after wearing a tight pair of socks on just one occasion.
The colour ultimately fades but raised lines may remain, according to the British Journal of Dermatology study.
However while they may be unattractive, the lesions appear to be harmless.
Because the condition has only recently been recognised, it as yet unclear whether scarring will be permanent.
Parents are nonetheless advised to choose their babies' socks carefully, ensuring that there is plenty of space between leg and sock.
The findings by a team at Washington University distinguish sock-line bands from other infant leg markings which can be associated with more sinister conditions like limb defects.
Blaming the sock
The team examined more than a dozen cases of these lesions reported in Europe and the US and concluded that socks were the culprit in the majority of them.
An 11-month-girl was one of the cases evaluated, having developed the marks at just one week of age after wearing a pair of tight socks.
"Sock line lesions appear to have a benign course," said one of the report's authors, Dr David Berk.
"However it is important that we recognise the disorder to allow us to collect data and cases, to better characterise how lesions develop."
Dr Colin Holden of the British Association of Dermatologists said: "While these bands are generally harmless, it is valuable for researchers to be able to discuss this possible new phenomenon in relation to already established skin disorders".