What Causes Bump On Thumb Knuckle?
Might be folliculitis, apply antibiotic ointment
Detailed Answer:
Hi
Welcome.
I have gone through your query
I would like to know since how long he had this?
What was the size of the lump?
Is there any pain?
Does he have any other medical illness?
Based on the information it might be folliculitis, that he has bursted. If possible kindly upload the picture, so that I'll get better idea what it might be.
Presently, I would suggest you to tell him not to touch it, wash it with cool water and antiseptic soap. Tap it dry using clean and sterile cotton, and apply neosporin ointment. If it is associated with pain, he can take over the counter NSAIDS like ibuprofen or paracetamol. Also I would suggest him not burst or sqeeze any lump, it is not advisable.
This provisional advice provided by me is based entirely on the input provided to me. I would suggest examination by the doctor.
I hope this suggestion might be of some help to you. Please accept my answer in case you do not have further queries.
Take care.