Evidence-based medicine must reign in dermatology
In 1980, a letter to the editor of Archives of Dermatology described the apparent effectiveness of dapsone in two cases of disseminated granuloma annulare. Since that time, a few similar cases have been reported, each referring back to the original report.
At the risk of sounding dogmatic, I can assure you that the lesions of granuloma annulare may improve while the patient is taking dapsone, but the drug itself is probably of no value.
I use this particular article as an example of a problem that is extremely common in dermatology. Since we have relatively few drugs in our therapeutic arsenal and care for hundreds of skin diseases, those few drugs tend to get utilized in situations far afield from their original intended use.
Anecdotal data is published to validate what is often inappropriate therapy, and once in the literature or in the public domain after a lecture or seminar, it is almost impossible to expunge the spurious information unless there is some horrible side effect. Almost never will the author or lecturer follow up his initial observation with a statement that his initial observation was incorrect and that the previous recommendations should be ignored.
It is very easy to employ magical thinking to convince oneself that a treatment is the direct cause of a miraculous improvement, even after subsequent data does not substantiate this. About 15 years ago, there was a wave of enthusiasm for the use of cimetidine for warts. I vividly recall a 14-year-old boy with at least 50 warts whose lesions resolved while on high-dose therapy for eight weeks. Based on this one case, I was positive that cimetidine was the next great advance in wart therapy.
A few years later, a well-designed placebo-controlled trial of this drug in verrucae was published. It demonstrated conclusively that the medication worked no better than a placebo. To my dying day, my emotional self will believe that the drug worked, although that notion is highly doubtful considering subsequent real data. Case reports continue to be published describing the benefits of this H2 blocker. The authors of these reports describe "mixed results" in previous studies. No, there are no mixed results. There is not a single controlled trial that shows improvement that is statistically superior to a placebo, particularly in adults.
MORE ARTICLES IN THIS ISSUE
Preventing and treating extrinsic and intrinsic skin aging and photoaging requires attacking these processes at the cellular level, experts say. A lifetime of healthy skin requires evaluating one's diet and lifestyle choices and selectively using vitamins and supplements.
A series of technological innovations has led to near-real-time, in vivo, three-dimensional optical imaging of skin up to a depth of 1 mm – with potentially a depth of up to 2 mm with clearing methods.
Results of a recent study to determine the effectiveness of noncoherent blue light in the intralesional photodynamic therapy (PDT) of basal cell carcinoma (BCC) found the treatment to be beneficial for a certain subgroup of patients.
Ever since Botox Cosmetic (onabotulinumtoxinA, Allergan) hit the market, it has gained enormous popularity in both the cosmetic and medical fields, and many other pharmaceutical and aesthetic companies have tried to produce additional botulinum toxins. Though Botox and Dysport (abobotulinumtoxinA, Medicis) remain the most popular, others are surfacing.
Sentinel lymph node biopsy (SLNB) is commonly considered beneficial for predicting prognosis in patients with cutaneous melanoma, although there has been no documented survival value. A new analysis casts doubt on the value of this practice, however.