The following factors predispose to keloids:
- race:
- there is a linear relationship between the amount of skin pigmentation and the likelihood of keloid scars; overall keloids are 5-15 times more common in darker-skinned races than in white, caucasian skin
- keloids are most common in Afrocaribbean and Asian skin
- early studies indicated that more common in those of Chinese descent compared to those with an Indian or Malaysian background
- age:
- keloids most commonly occur between 10-40 years of age
- they only rarely arise de novo elderly subjects
- site; in order of decreasing frequency, keloids occur most commonly at the:
- sternum
- shoulder
- neck
- face
- extensor surface of limbs
- truncal sites other than sternum
- gender:
- contradictory studies have suggested the highest prevalence in young females, particularly when there are keloids at multiple sites and there is a strong family history(1); this may reflect the higher rate of pierced ears in this group
- in other age groups, there is no gender bias
- genetic:
- as suggested by the racial predisposition
- associated with a number of genetic loci
Ref:
(1) Bayat A, Arscott G et al. Br J Plast Surg (2005); 58(1): 28-37.