Between December 2012 and June 2014, 164 patients attended our facility and of these, 100 agreed to participate in the study. The male: female ratio was 1:2.2. There was one patient of Black African descent, five of Irish Traveler descent and 94 of White European descent. The mean age was 53.7±11.3(range 31.1-80) years. The mean number of skin tags was 10.5±18.4 (range 0-135). Tags were present in 85 patients and absent in 15. Skin tags were present only in the axillae in 30 patients, only on the neck in 11 patients and 44 patients had skin tags in both the axillae and the neck. 62 patients had three or more skin tags while 38 had less than three. 12 patients were current smokers while 88 were previous or never smokers. 14 patients reported a current or past history of sleep apnea while 4 had previous bariatric surgery. 41 patients were currently taking antihypertensive therapy (59 were not), 37 were taking medication for type 2 diabetes (none had type 1 diabetes) and 36 patients were taking lipid lowering therapy (either statin or fibrate). Of the 37 patients with diabetes, 35 had skin tags(94.6%), compared to 50 of 63 patients without diabetes(79.4%, p=0.039). Put another way, 59% of those with skin tags, compared to 13% of those with no tags had diabetes. Skin tags were present in 79.7% of female and 96.8% of male patients(p=0.027). 45.8% of patients with skin tags compared to 13.3% with no tags were on antihypertensive therapy(p=0.018), while 38.8% and 20%, respectively, were on lipid lowering therapy(p=0.16).
The anthropometric and metabolic characteristics of study participants with any skin tags compared to those with no skin tags are presented in table 1. Those with any skin tags had higher SBP and fasting blood glucose and a higher HbA1c. There was a (statistically non-significant) trend to higher THDLR in those with skin tags, consistent with them being more insulin resistant. Likewise, there were non-significant trends to increased weight and diastolic blood pressure in those with versus those without any skin tags.
Results from logistic regression analyses, with the presence or absence of any skin tags as the binary dependent variable are shown in table 2. For every rise of 1mmHg in SBP, the likelihood of having any skin tags increased by 7.5%(p=0.005) while patients with hypertension were 5.5 times more likely to have skin tags than patients with normal SBP(p=0.031). However, the association with hypertension was no longer significant after adjusting for age and sex, both of which had a borderline significant association with skin tag presence, as shown in table 2. There were non-significant trends to men having a 7.6 times greater likelihood than women to have skin tags(p=0.055) while for every year older, there was a non-significant trend to a 5.1% increase in the likelihood of skin tags(p=0.067). Similarly, there was a non-significant trend to a 4.55-fold increased likelihood of any skin tags in patients with diabetes compared to those without diabetes(p=0.055). Those with tags had a higher HbA1c, but not after adjusting for age and sex. The borderline difference observed in the THDLR using the unpaired t-test was not replicated using logistic regression in unadjusted or adjusted analyses.
In linear regression models with the number of skin tags being the dependent or outcome variable, male sex was strongly associated with skin tags (ß=15.85 [8.61, 23.09], p<0.001). In other words, men had approximately 16 more skin tags than women. There was no statistically significant association between age and skin tags (ß=0.32 [-0.003, 0.63], p=0.052).
Next, we compared anthropometric and metabolic characteristics in participants with both cervical and axillary skin tags to those who had no skin tags(Supplementary table 1). As before, there were significant differences in glucose and HbA1c, but in addition to SBP, diastolic blood pressure was also elevated and there was a significant difference in weight of 14.8 kg in those with axillary and cervical tags compared to those with none. We compared patients who had axillary skin tags versus those without axillary skin tags, with the only significant difference being greater height and weight in those with axillary skin tags(Supplementary table 2). Finally, we found that compared to patients without cervical skin tags, those with cervical skin tags had higher systolic and diastolic blood pressure, with higher BMI and a (borderline significant) higher waist circumference and weight(Supplementary table 3).