Sign-in to Ask A Doctor - 24x7
OR
Sign in with GoogleGet your health question answered instantly from our pool of 18000+ doctors from over 80 specialties
Reddish Itchy Bump On The Thigh. Black Scar Formation. Why?
Years ago one day I had this red bump the size of a quarter on my thigh. I scratched it and it turned red from the scratching. The next day it turned black. Since 2005 I have had this black pigmentation on my thigh. It does not hurt or itch or feel any different from the rest of my skin. It is like a birth mark. But over the last three 3years it has started to fade.
What could have caused this?
What could have caused this?
Mon, 8 Apr 2013
Dear Kimacholonu,
Hi and welcome to Healthcare Magic.
The black pigmentation on your thigh is known as Post Inflammatory Hyperpigmentation/ Post Inflammatory Hypermelanosis (PIH). It is a condition of the skin arising from trauma ( of any nature) to the skin resulting healing with pigmentation.
Now to explain in your situation, you might have had a rash arising from either insect bite or due purpura (extravasation of blood in skin due to many a causes) or due to so many reasons. It is a superficial skin change in first instance. But then as you scratched, it caused deeper injury to the skin. Due to this deeper injury it stimulated the melanocytes (the color producing cells of the skin) which turned the rash into black pigmentation. This is totally a normal process which is a part of healing phenomenon in any injury to skin. So if the injury is superficial it does not generally leave a mark but if the injury is deep it will leave blackish brown mark. PIH is an asymptomatic (without any symtom of pain or itching) condition.
Now you should also understand that our skin is daily renewing itself so the pigmentation which is deeper it gets lighter as the skin is renewed. After few years of period it will be faintly visible or not visible at all !!
I hope you got your answer and next time you will ask the person in circle that not to scratch or rub any injury/ Rash.
With best health wishes
Dr Sanjay K Kanodia
Hi and welcome to Healthcare Magic.
The black pigmentation on your thigh is known as Post Inflammatory Hyperpigmentation/ Post Inflammatory Hypermelanosis (PIH). It is a condition of the skin arising from trauma ( of any nature) to the skin resulting healing with pigmentation.
Now to explain in your situation, you might have had a rash arising from either insect bite or due purpura (extravasation of blood in skin due to many a causes) or due to so many reasons. It is a superficial skin change in first instance. But then as you scratched, it caused deeper injury to the skin. Due to this deeper injury it stimulated the melanocytes (the color producing cells of the skin) which turned the rash into black pigmentation. This is totally a normal process which is a part of healing phenomenon in any injury to skin. So if the injury is superficial it does not generally leave a mark but if the injury is deep it will leave blackish brown mark. PIH is an asymptomatic (without any symtom of pain or itching) condition.
Now you should also understand that our skin is daily renewing itself so the pigmentation which is deeper it gets lighter as the skin is renewed. After few years of period it will be faintly visible or not visible at all !!
I hope you got your answer and next time you will ask the person in circle that not to scratch or rub any injury/ Rash.
With best health wishes
Dr Sanjay K Kanodia
I find this answer helpful
2 Doctors agree with this answer
Note: Hope the answers resolves your concerns, however for further guidance of skin related queries consult our Dermatologist.Click here to book a consultation
Disclaimer: These answers are for your information only and not intended to replace your relationship with your treating physician.
This is a short, free answer.
For a more detailed, immediate answer, try our premium service
[Sample answer]
Related questions you may be interested in
Recent questions on Melanocyte
Loading Online Doctors....