Acrochordon (skin tag)
Skin tag; fibroepithelial polyp; "tag"; soft fibroma; "Birt-Hogg-Dubé acrochordon" (when in syndromic context)
The acrochordon — universally known as a "skin tag" — is a small, soft, pedunculated, flesh-coloured to lightly hyperpigmented papule, occurring in intertriginous and friction-bearing sites (neck, axillae, eyelids, groin, inframammary fold). Acrochordons are essentially universal in adulthood, increasing in number with age, obesity, type 2 diabetes, insulin resistance and pregnancy. They are entirely benign with no malignant potential. The skin-oncology relevance lies in two contexts: (1) the rare confusion with pedunculated melanoma, BCC, neurofibroma or other neoplasm — biopsy any unusually sized, pigmented, growing or atypical lesion; and (2) the recognition that multiple acrochordons in unusual sites in a young patient can be an early marker of Birt-Hogg-Dubé syndrome (FLCN — fibrofolliculomas + pulmonary cysts + RCC), where the "skin tags" are histologically and molecularly fibrofolliculomas. Multiple acrochordons are also associated with insulin resistance and metabolic syndrome — a paraneoplastic-like marker of glucose dysregulation rather than malignancy.
Clinical features
- Soft, pedunculated, flesh-coloured to lightly hyperpigmented papule, 1–5 mm (occasionally larger).
- Slow-growing; asymptomatic until traumatised, twisted (haemorrhagic infarction → black tag) or caught on clothing.
- Distribution — neck, axillae, eyelids, groin, inframammary fold; occasionally face / trunk.
- Median age — adults; prevalence rises steeply with age, reaching universal in older adults.
- Associations:
- Obesity, type 2 diabetes, insulin resistance, metabolic syndrome.
- Pregnancy (often regress post partum).
- Acromegaly.
- Acanthosis nigricans (frequently co-exist).
- Variants — broad-based fibroma molle, filiform / threadlike, pedunculated.
Differential diagnosis
- Most acrochordons are clinically obvious; biopsy is unnecessary.
- Biopsy if any of the following:
- Unusually large size (>1 cm).
- Pigmentation (especially asymmetric or atypical) — to exclude melanoma.
- Friable / bleeding / ulcerated.
- Rapid growth.
- Indurated base.
- Diagnostic uncertainty.
- Differentials — pedunculated seborrhoeic keratosis, polypoid pyogenic granuloma, polypoid melanoma (pedunculated melanoma exists and is regularly missed clinically), pedunculated BCC, neurofibroma (NF1 marker — "buttonhole" sign on palpation), fibrofolliculoma of Birt-Hogg-Dubé (multiple skin-tag-like papules on face / neck / upper trunk in a young to middle-aged patient — see monograph), filiform wart.
Multiple acrochordons → consider underlying conditions
- Birt-Hogg-Dubé syndrome — multiple skin-tag-like papules that are frequently fibrofolliculomas / trichodiscomas on histology; in young to middle-aged patients with face / neck / upper trunk distribution. Always consider in any patient with dozens of acrochordons appearing before age 40 — see monograph.
- Insulin resistance / metabolic syndrome — multiple acrochordons are an independent marker; consider HbA1c screening.
- Acromegaly — multiple skin tags + soft-tissue overgrowth + facial coarsening.
- Cowden syndrome — among multiple cutaneous markers, but trichilemmomas and palmoplantar pits are more characteristic; see monograph.
Management
- Reassurance — typical asymptomatic skin tags require no treatment.
- Removal options (cosmetic / functional / persistently irritated):
- Snip excision with iris scissors at the base — quick, simple, most common; minimal bleeding.
- Cryotherapy.
- Electrodesiccation / cautery.
- Ligation.
- Laser ablation.
- Histology should be performed if any clinical doubt about diagnosis.
- Multiple acrochordons in a young patient — consider syndromic context (Birt-Hogg-Dubé, Cowden), insulin resistance screening, acromegaly screen if other features.
- Counsel on weight management / glycaemic control if metabolic context.
References
- Akpinar F, Dervis E. Association of skin tag with insulin resistance and metabolic syndrome. N Am J Med Sci; 2012.
- Sand FL, Thomsen SF. Skin tags — review. Dermatology; 2018.
Spot a correction?
If any clinical statement, citation or link on this page needs updating, please email admin@skinoncology.net with the page name, the proposed correction and the supporting source.