History and exam
Key diagnostic factors
common
presence of risk factors
Key risk factors include a personal or family history of keloids, local skin tension, and follicular inflammation/infection.
history of inciting event (e.g., body piercing, surgery, vaccination)
Typically there is an inciting event that has caused damage to the skin.[1] There may be an interval of months between the damage and the first appearance of the scar.
Occasionally, there will be no clear history of an inciting event.
slow growth/lack of spontaneous regression
Keloids are typically slow-growing lesions and fail to regress in most cases.
erythematous, smooth, and shiny elevated scar with overhanging edge
Typically, the keloid scar grows beyond the boundaries of the original injury.
Other diagnostic factors
uncommon
itch or pain
These symptoms tend to be more intense during the active growth phase.
Risk factors
strong
history of prior keloid
A history of prior keloid scarring in a patient is associated with a strong risk of occurrence at other sites.[19]
Research on the differential gravity of risk factors for keloid development is limited and inconsistent, and thus the classification into strong and weak may change as new evidence emerges.[3]
local skin tension
Keloids occur most frequently in areas of the body subject to stretch including the upper back/shoulders, chest, and lower abdomen.[20]
Research on the differential gravity of risk factors for keloid development is limited and inconsistent, and thus the classification into strong and weak may change as new evidence emerges.[3]
follicular inflammation/infection
If the skin gets rewounded, becomes infected, or consistently inflamed during healing, the risk of keloid scar formation is higher by virtue of a prolonged inflammatory response.[20]
Research on the differential gravity of risk factors for keloid development is limited and inconsistent, and thus the classification into strong and weak may change as new evidence emerges.[3]
family history of keloid and genetic factors
Numerous patients with keloid scars report a positive family history of pathological scarring, which may suggest that there are genetic factors implicated in the pathophysiology. Studies of familial keloid cases have identified associated single nucleotide polymorphisms and susceptibility loci on chromosomes 1q41, 2q23, 7p11, and 10q23.31 in Japanese, African-American, and Han Chinese families.[10][11][12] Responsible genes have not yet been identified.
Research on the differential gravity of risk factors for keloid development is limited and inconsistent, and thus the classification into strong and weak may change as new evidence emerges.[3]
weak
dark skin types
Keloids are most common among Afro-Caribbean people.[3] Some studies report an increased prevalence in Asian people compared with white people.[4][5]
Research on the differential gravity of risk factors for keloid development is limited and inconsistent, and thus the classification into strong and weak may change as new evidence emerges.[3]
hormonal status
Keloid scars often develop or worsen at puberty and during pregnancy, and an improvement is often noted after the menopause.[16] Oestrogen has vasodilatory action, and hence may enhance levels of inflammation.[17]
Research on the differential gravity of risk factors for keloid development is limited and inconsistent, and thus the classification into strong and weak may change as new evidence emerges.[3]
systemic conditions (e.g., hypertension, atopic eczema, Castleman disease)
Keloids have been associated with a number of systemic conditions, including hypertension, atopic eczema, and conditions related to increased levels of cytokines such as Castleman disease.[4][17] An analysis of UK Biobank data found a statistically significant association between excessive scarring and comorbid atopic eczema in Asian, white, and black patients.[4]
Research on the differential gravity of risk factors for keloid development is limited and inconsistent, and thus the classification into strong and weak may change as new evidence emerges.[3]
lifestyle factors
Several lifestyle parameters may exacerbate pre-existing scars or surgery-induced inflammation, including vigorous physical activity (e.g., competitive athletes, manual workers).[17]
Research on the differential gravity of risk factors for keloid development is limited and inconsistent, and thus the classification into strong and weak may change as new evidence emerges.[3]
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