The etiology of acrochordons is unknown. It was hypothesized in the past that skin tags occur in areas where elastic tissue has been lost.⁶,⁷ According to this concept, the loss or sparsity of elastic tissue, which is a normal consequence of aging, could result in the development of acrochordons; however, this theory is disputed.⁸ Low-grade human papillomavirus (HPV 6 and 11) infections may be related to the genesis of skin tags,⁹,¹⁰ but this relation is also disputed.¹¹

A genetic etiology of acrochordons has not been established, although a link is possible because skin tags have several syndromic associations. Acrochordons may be part of the Birt-Hogg-Dubé syndrome (BHD syndrome, 17p11), basal cell nevus syndrome (Gorlin-Goltz syndrome, 1q34, 9q22, or 10q24), or Cowden syndrome (10q23).¹² Birt-Hogg-Dubé syndrome is a rare autosomal dominant genodermatosis caused by a mutation of the BHD gene and is hallmarked by a triad of multiple trichodiscomas, fibrofolliculomas, or acrochordons, and is also associated with several internal malignancies (kidney and less commonly thyroid cancer). However, this syndrome has not been reported in the periocular region, although a solitary eyelid trichodiscoma has been described.¹³ Gorlin-Goltz syndrome is an autosomal dominant disease characterized by the early onset of multiple basal cell carcinomas, along with other findings including the childhood onset of acrochordon-like growths, which may occasionally harbor basal cell carcinoma.³,¹⁴,¹⁵

Other predisposing factors or associated conditions include obesity, pregnancy, diabetes, insulin resistance, and hyperlipidemia.²,¹⁶,¹⁷ Acrochordons also appear to increase in number during periods of weight gain.²,¹⁷ The relation to insulin resistance and type 2 diabetes appears to be robust,¹⁸ and in addition, one recent study found that 45.8% of subjects with skin tags suffered from hyperlipidemia, 65.0% from hypertension, and 70.8% from obesity.¹⁹ In short, the risk of developing a metabolic syndrome is significantly higher in patients with skin tags.¹⁷

Elevated levels of growth hormone may also be associated with the development of fibroepithelial polyps as skin tags are one of the more frequent cutaneous manifestations of acromegaly.²⁰ It is not clear whether excessive levels of growth hormone per se are responsible for the evolution of skin tags directly or whether they develop as a consequence of insulin resistance and dyslipidemia.²⁰ Although a possible association between skin tags and colonic polyps has been proposed in the past, this relation is currently disputed by most researchers.¹,²¹,²²

An important but frequently overlooked possible predisposing factor is chronic friction or irritation of the skin, as acrochordons are well known to develop in friction-prone areas like the axilla, neck, trunk, or eyelids and are associated with activities like shaving, eye rubbing, or wearing jewelry.²³,²⁴ A recent study found that the mast cell count in acrochorda was significantly higher than in controls.²³ Mast cells are increased in
number in many skin diseases, and they are particularly recruited to sites of injury as an early response to trauma. These mast cells subsequently upregulate their tumor necrosis factor α content to direct the tissue response to injury.²³,²⁵

Acrochordons are extremely common in adulthood. It is an incidental finding in roughly 50% to 60% of patients older than 50 years presenting to a dermatology clinic. Nevertheless, the vast majority of these patients are not bothered by them, and only 0.5% may present to the clinician for excision of these lesions.¹,²⁴ This is because the popular belief among patients is that skin tags are an acceptable sign of aging.¹ The condition is first observed in the second decade of life, after which there is a steady increase in frequency up to the 5th decade, then the number of individuals with skin tags starts to plateau.¹,²⁶ There is no sex predilection, but as was mentioned earlier, fibroepithelial polyps are more common in obese diabetics.¹,²,³,⁴,¹⁶,¹⁷,¹⁸,¹⁹