Although topical corticosteroids are the mainstay for treatment of AD, many patients report treatment resistance after a period of a few doses or longer.6-9 There is strong evidence demonstrating rapid corticosteroid receptor downregulation in tissues after corticosteroid therapy, which is the accepted mechanism for tachyphylaxis, but the timing of this effect does not match up with clinical experiences. The physiologic significance of corticosteroid agonist-induced receptor downregulation is unknown and may not have any considerable effect on corticosteroid efficacy.3 A systematic review by Taheri et al3 on the development of resistance to topical corticosteroids proposed 2 theories for the underlying pathogenesis of tachyphylaxis: (1) long-term patient nonadherence, and (2) the initial maximal response during the first few weeks of therapy eventually plateaus. Because corticosteroids may plateau after a certain number of doses, natural disease flare-ups during this period may give the wrong impression of tachyphylaxis.10 The treatment “resistance” reported by the patients in our study may have been due to this plateau effect or to poor adherence.
Our finding that nearly all patients had rapid improvement of AD with the topical corticosteroid is not definitive proof but supports the notion that tachyphylaxis is largely mediated by poor adherence to treatment. Patients rapidly improved over the short study period. The short duration of treatment and multiple visits over the study period were designed to help ensure patient adherence. Rapid improvement in AD when topical corticosteroids are used should be expected, as AD patients have rapid improvement with application of topical corticosteroids in inpatient settings.11,12
Poor adherence to topical medication is common. In a Danish study, 99 of 322 patients (31%) did not redeem their AD prescriptions.13 In a single-center, 5-day, prospective study evaluating the use of fluocinonide cream 0.1% for treatment of children and adults with AD, the median percentage of prescribed doses taken was 40%, according to objective electronic monitors, even though patients reported 100% adherence in their medication diaries.Better adherence was seen on day 1 of treatment in which 66.6% (6/9) of patients adhered to their treatment strategy versus day 5 in which only 11.1% (1/9) of patients used their medication.1
Topical corticosteroids are safe and efficacious if used appropriately; however, patients commonly express fear and anxiety about using them. Topical corticosteroid phobia may stem from a misconception that these products carry the same adverse effects as their oral and systemic counterparts, which may be perpetuated by the media.1 Of 200 dermatology patients surveyed, 72.5% expressed concern about using topical corticosteroids on themselves or their children’s skin, and 24% of these patients stated they were noncompliant with their medication because of these worries. Almost 50% of patients requested prescriptions for corticosteroid-sparing medications such as tacrolimus.1 Patient education is important to help ensure treatment adherence. Other factors that can affect treatment adherence include forgetfulness; the chronic nature of AD; the need for ongoing application of topical treatments; prohibitive costs of some topical agents; and complexities in coordinating school, work, and family plans with the treatment regimen.2
We attempted to ensure good treatment adherence in our study by calling the patients in the intervention group twice daily. The mean improvement in EASI, TLSS, and IGA scores was higher in the intervention group versus the control group, which suggests that patient reminders have at least some benefit. Because AD treatment resistance appears more closely tied to nonadherence rather than loss of medication efficacy, it seems prudent to focus on interventions that would improve treatment adherence; however, such interventions generally are not well tested. Recommended interventions have included educating patients about the side effects of topical corticosteroids, avoiding use of medical jargon, and taking patient vehicle preference into account when prescribing treatments.8 Patients should be scheduled for a return visit within 1 to 2 weeks, as early return visits can augment treatment adherence.14 At the return visit, there can be a more detailed discussion of long-term management and side effects.8
Limitations of our study included a small sample size and brief treatment duration. Even though the patients had previously reported treatment failure with topical corticosteroids, all demonstrated improvement in only 1 week with a potent topical corticosteroid. The treatment resistance that initially was reported likely was due to poor adherence, but it is possible for AD patients to be resistant to treatment with topical corticosteroids due to allergic contact dermatitis. Patients could theoretically be allergic to components of the vehicle used in topical corticosteroids, which could aggravate their dermatitis; however, this effect seems unlikely in our patient population, as all the patients in our study showed improvement following treatment. Another study limitation was that adherence was not measured. The frequent follow-up visits were designed to encourage treatment adherence, but adherence was not specifically assessed. Although patients were encouraged to only use the desoximetasone spray during the study, it is not known whether patients used other products.
Some AD patients exhibit apparent decreased efficacy of topical corticosteroids over time, but this tachyphylaxis phenomenon is more likely due to poor treatment adherence than to loss of corticosteroid responsiveness. In our study, AD patients who reported treatment failure with topical corticosteroids improved rapidly with topical corticosteroids under conditions designed to promote good adherence to treatment. The majority of patients improved in all 4 parameters used for evaluating disease severity, with 100% of patients reporting improvement in pruritus. Intervention to improve treatment adherence may lead to better health outcomes. When AD appears resistant to topical corticosteroids, addressing adherence issues may be critical.