“Red blotchy spots on forearms?”
Sometimes when I bump my forearm into something like a chair a red blotchy spot develops under the skin shortly thereafter. It fades slowly over a 4-7 day period. What causes this?
Male | 64 years old
4 Answers
See your dermatologist to go over this with you.
Suzanne Sirota Rozenberg, DO, FAOCD, FAAD
Suzanne Sirota Rozenberg, DO, FAOCD, FAAD
Sometimes pressure can cause a localized skin reaction called dermatographism. No one knows the reason why. A steroid cream may help resolve the condition sooner. Superficial injury can also cause local blood vessels to leak, causing a bruise. This too slowly resolves.
Stephen Schleicher, MD
Stephen Schleicher, MD
These spots are minor bruises from the incidental traumas such as you describe. Small amounts of blood are forced out of superficial blood vessels and become free in the superficial soft tissue. This resolves in a few days; the more severe the bruising, the longer the resolution will take.
You have what we call actinic purpura. Sun damaged skin is more fragile and becomes thinner. The slightest bump to most commonly, the forearms,can then lead to bleeding under the skin which then resolves after a week or two.
