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Painful like walking on a tiny pebble: Porokeratoma

Dr. Donald Pelto talks about porokeratoma or seed corn, a painful small hard bump that can be confused with a callus or a war

Painful like walking on a tiny pebble: Porokeratoma


Have you ever felt pain on the bottom of the foot as if you were constantly walking on a small pebble, especially under a bony prominence? This could be a porokeratoma: a small hard round bump that develops due to a clogged sweat gland.

Typically confused with a callus, a porokeratoma has a yellowish or whitish center like a “seed”. For this reason, it is also known as “seed corn.” As little as a sesame seed, it is hard and can be slightly elevated. Unlike a wart it does not have blackish spots.

Despite being tiny, it can leave you limping with pain and it is made worse by wearing tight shoes or walking on hard surfaces barefoot. If you think about a magnifying glass, how it focuses all the light into one central area, the pain on a porokeratoma is focused on that central pit.


Trimming it down

The best way of treating the porokeratoma is by trimming down all the hard area, but this should only be done by a professional because we also cut out the central area of the circle. After that we usually put on a circle pad with a little salicylic acid - which is used to soften the skin - and cover it with a bandage for a few days.

If it continues to happen, we suggest cutting out a portion of the shoe liner to take the pressure off of that area. Sometimes a cushioning pad or an orthotic helps. Although uncomfortable and painful, a porokeratoma does not tend to cause foot complications.

Whenever you are dealing with pain on your feet, you should seek a podiatrist's help as the solution could be simple and give you instant relief after removing a callus, a corn, an ingrown toenail or, in this case, cutting off a porokeratoma. 

Call 508-757-4003 or text 508-625-7775 for an appointment in Worcester and Westborough. Same day visits might be available.


Dr. Donald Pelto Dr. Donald Pelto Dr. Donald Pelto is a Podiatrist at Central Massachusetts Podiatry, in Worcester and Westborough. Author of several books on foot health, he also speaks Portuguese and English. He likes to go on family hikes and loves learning and talking about health related topics and healthy life hacks. Watch some of his interviews about health and video lectures on

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