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Dermatology Urban Legends

Dawn Sammons, DO, with Oakview Dermatology, presented on some of the pervasive beliefs patients and providers still have at the 2019 Fall Clinical Dermatology Conference.

We need ways to talk to our patients, said Dr Sammons, noting that many come in after using Google and often feel like they understand what they have. In addition, patients could have seen other providers who have their own opinions about a condition not based on data.

One common belief is that antibiotics lower the efficacy of birth control. Dr Sammons said she receives many phone calls from patients after a pharmacist tells them the antibiotic might affect the efficacy of their birth control. According to her, the case reports that this belief is based on were from the early 20th century. Newer studies have shown that serum levels of over-the-counter contraceptives are not affected by antibiotics, with the exception of rifampin (Rifadin), mainly used for hidradenitis suppurativa. She recommended educating patients and pharmacists when prescribing antibiotics about whether the therapy will affect contraceptives.

Another common belief is that retinoids have to be applied at night because they are sensitive to sunlight. This was based on early retinoids, which were deactivated by UV exposure, said Dr Sammons. Most products that are prescribed today are photostable for about 8 hours. While there is an increase in photosensitivity, she added, but patients can use retinoids in the morning if they are more likely to be adherent.

In hair loss, patients may say they do not want to use minoxidil because they will have to use the product forever. While this is true for female pattern hair loss, other types of hair loss may not need continuous use. Female pattern hair loss is a chronic condition, said Dr Sammons. Patient expectations should be discussed as they can become impatient, stop the therapy too early, and believe any excess shedding is caused by the drug. It can take about 6 months for the therapy to be truly effective, she added.

For dermatologists, a common belief is to not use epinephrine when injecting lidocaine into the toes and fingers. According to Dr Sammons, the cases where necrosis was seen following epinephrine use in these areas had many flaws, including inappropriate tourniquet use. The good news is new evidence does not support this avoidance, said Dr Sammons. She recommended buffering because lidocaine is slightly acidic, but this therapy combination can be used.

Another common belief in dermatology is that cosmetic therapy should be delayed by 6 months following the use of isotretinoin. The American Society of Dermatologic Surgeons (ASDS) task force consensus statement said treatment does not need to be delayed following isotretinoin therapy, so long as it is non-fractionated ablative therapies, said Dr Sammons.

Dr Sammons reviewed allergies to sulfa antibiotics and the risk of an allergic reaction to dapsone. She discussed a study that showed 10% of patients who were allergic to sulfa antibiotics also had a reaction to a non-antibiotic sulfa therapy. However, more patients who were allergic to sulfa drugs also had a reaction to penicillin. The take home, said Dr Sammons, is these patients are just more likely to have an allergic drug reaction in general.

Other urban legends Dr Sammons reviewed included testing with biologics, which was not found to be absolutely useful, aside from baseline tuberculosis screening, and testing with isotretinoin, which did not require continuous testing for most patients after 2 months. She also reviewed the risk for liver failure associated with terbinafine, which she noted caused less liver injuries than acetaminophen and antibiotics. In addition, she added that every case of liver injury was associated with major adverse effects. She tells patients to call her if they experience any symptoms.

According to Dr Sammons, 80% of patients with psoriasis are not receiving treatment other than topicals regardless of psoriasis severity because practitioners are nervous about biologics. When discussing risk associated with tumor necrosis factor (TNF) inhibitors, which ranges from about 0.5% to 4.5%, Dr Sammons said the provider’s job is to have a conversation with a patient about the risk and how likely they are to experience it. For example, Dr Sammons noted that the risk of dying while driving home is higher than the risk of malignancy associated with TNF inhibitors. “Every single one of us are going to get in a car and not think twice about it,” she said, adding that it is important providers help patients understand this risk to make better treatment decisions.

There is a lot of misconceptions, which are based on some true information, concluded Dr Sammons. She stressed the importance of being able to answer questions patients and other providers have regarding these urban legends.


Sammons D. The urban legends of dermatology. Presented at: 2019 Fall Clinical Dermatology Conference; October 20, 2019; Las Vegas, NV.

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