Keloid disease is a fibro proliferative skin tumor and occurs after a skin trauma in genetically vulnerable individuals. Etiology of keloid is unclear. Causative factors for keloid are increased familial aggregation, a higher prevalence in certain races, parallelism in identical twins, and alteration in gene expression. It appears that the surroundings activate the disease in genetically susceptible individuals. Several genes are considered responsible for keloid disease, but no single gene mutation has thus far been found to be responsible. Therefore, we should apply a combination of methods such as association, gene-gene interaction, epigenetics, linkage, gene expression, and protein analysis to find out the keloid etiology. Incidence of familial keloid is common in Africans but is uncommon in Indian population. It may be due to autosomal dominant or autosomal recessive inheritance.
Keloids are benign hyper proliferative reaction of dermal fibroblasts demonstrated by the excessive deposition of extracellular matrix components, especially collagen, fibronectin, elastin, proteoglycans, and growth factors such as transforming growth factor (TGF) β. Modification in growth factors, excessive collagen, genetic and immunological factors contribute in keloid formation. Risk factors for keloid formation in susceptible persons are trauma, foreign-body reactions, infections, and endocrine dysfunctions. Keloid disease affects both sexes equally [
A 35 years lady presented with flat keloid lesion of upper chest for the last one year. There was history of itching in the swelling. She complained of similar disease in her daughter and son. She was diagnosed as having keloid as this developed after minor scratch over upper chest. On examination, there was a flat 3.5 × 2 cms, reddish brown colored lesion with irregular and raised margins. Daughter and son also had similar lesion on upper chest without any history of trauma (
Keloids and hypertrophic scars are different clinically and pathologically. Keloid may appear spontaneously or following a trauma. It expands beyond the margin of the wound, and persists and may expand for numbers of years. Histologically, keloids are characterized by a greatly expanded dermis occupied by large, hyalinized collagens fibers that are strongly eosinophilic. Keloids show dermal nodules with less distinct borders [
Pathogenesis of Keloid Disease: Numerous theories have been proposed for the pathogenesis of keloids. Ethnicity affects the prevalence of keloid disease. Patients with darker skin, however, have a higher prevalencethan those with lighter pigmentation. Both autosomal dominant with incomplete penetrance as well as autosomal recessive modes of inheritance is found among families with keloid disease.
Several Mendelian disorders can be associated with keloids as part of their clinical features and keloids can develop in person with a connective-tissue disorder.
Keloids are enriched in growth factors and extracellular matrix (ECM) molecules and ECM molecules play an important role in skin structure; therefore, disruption of the ECM could be responsible for abnormal scar tissue formation. Keloid tissue is characterized by the accumulation of ECM, especially collagen. Keloid-derived fibroblast cells exhibit high expression of TGF β1 and TGF β2 and thus results in excessive collagen synthesis. TGF β3 stimulates collagen synthesis via TGF β1 and TGF β2. TGF β1 is expressed by neovascular endothelial cells in the primary stages of fibrosis in keloid tissue, which therefore stimulate the expression of type I and VI collagens at a high level. TGF β1 is a key factor in keloid development and regulates the expression of multiple downstream genes. Exogenous TGF β1 up regulates the expression of platelet derived growth factor (PDGF) α receptor in keloid-derived fibroblast cells but not in non-keloid-derived fibroblast cells. It has also been shown that TGF β stimulates the expression of vascular endothelial growth factor (VEGF) in keloid fibroblasts as well. SMAD2 and SMAD3 play a critical role in TGF β-induced fibrosis in the formation of keloids [
No study has yet found any association between TGF β family members and keloid disease in Caucasian populations in spite of strong evidence from expression studies. Polymorphisms in TGFB1, TGFB2, and TGFBR1 were not linked with keloids or hypertrophic scars [
Familial keloids manifest autosomal dominant inheritance. Bloom reported 31 mostly European keloid pedigrees, including one of African origin [
Treatment of keloid lesion depends upon many factors like, size of lesion, location, depth of lesion, age of patient, and past response to treatment. Surgical excision, radiation, pressure therapy, cryotherapy, intralesional injection of corticosteroids, interferon and fluorouracil, topical silicone and other dressings, and pulse-dye laser treatment have been found to induce some degree of regression. Other therapies including intralesional calcium channel blockers, bleomycin, cyclosporine, topical retinoic acid and imiquimod have shown promise in the treatment of keloids. Yet there is no universally accepted treatment protocol despite the broad range of treatment modalities. In most instances these therapies are used as an adjuvant to surgical excision [
Familial keloids appear to be most commonly manifested autosomal dominant or semidominant inheritance, and there may be familial patterns of keloid distribution. As post-surgery keloid is common in these families, prophylactic measures should be taken during surgery along with preoperative counseling.
Snigdha Goyal,Isha Saini,Sunder Goyal, (2015) Familial Keloid in Indian Scenario: Case Report and Review of Literature. Open Access Library Journal,02,1-4. doi: 10.4236/oalib.1101578