All Things Contact Dermatitis™ SEPTEMBER 2017 NEWS & NOTES
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ISSUE 21 all things contact dermatitis™ SEPTEMBER 2017 NEWS & NOTES IN THIS ISSUE Corticosteroids: A Two-Edged Sword ....................................................................... p1 Using Social Media to Help Build Your Practice ............................................................... p4 Dear Readers, Corticosteroids: A Two-Edged Sword In the 2017 Winter and Spring issues of this newsletter, we shared tactics for re- taining and building your patient base. orticosteroids are the primary (symptomatic) treatment for inflammatory skin We introduced the concept of the net Cdiseases. Unfortunately, corticosteroids, which can be administered in creams, promotor score for gauging your pa- gels, lotions, ointments, suppositories, intramuscular or intravenous solutions, or tients’ satisfaction with your practice orally, really are a two-edged sword because they are also sensitizing substances. The and discussed the importance of devel- most common reaction to corticosteroids is delayed type IV hypersensitivity, but type oping a website as part of that strategy. I allergic reactions have also been reported. Because patients are often prescribed This series now closes with a final article corticosteroids to treat a variety of dermatitic conditions, diagnosing allergic contact that explores additional options for en- dermatitis to the medicine itself can be challenging. In a recent retrospective analysis gaging current and future patients using of almost 18,000 patients conducted by the North American Contact Dermatitis Group tools such as Google Places and social (NACDG), the overall prevalence of sensitivity to corticosteroids was 4.1%, which is media. We hope these articles have consistent with earlier international reports. Given the widespread therapeutic use of enhanced your appreciation of what it corticosteroids, the American Contact Dermatitis Society recognized this group of takes to become and remain a success- drugs as the Allergen of the Year in 2005. ful practice in today’s ever-changing en- vironment. In 1989 Coopman and coworkers classified corticosteroids into 4 groups (A, B, C, and D) Even as one series ends, another begins. that reflect structural distinctions between groups and highly homogenous molecular This time the topic is motivated by the structures of the substances within a group (Table 1). Later, Group D was divided into many questions we receive on the topic subgroups D1 (stable esters) and D2 (labile esters) based on chemical substitutions of corticosteroids—a group of allergens on the corticosteroid backbone. In 2011 Baeck and coworkers introduced a new class- far too complex to discuss in a single ar- ification system that condensed corticosteroids into three clusters (Table 1). ticle. In this issue you will find an over- Their simplification was based on identification of two patient profiles: view of corticosteroids: how they are those who reacted to corticosteroids from only one group and classified and the underlying clinical im- those likely to react to the entire spectrum of cortico- plications for diagnostic patch testing. steroids. Hence, nonmethylated, nonhalogenated Future articles will offer a more in-depth allergic corticosteroids were classified as Group 1 look at the specific markers that are (i.e., Coopman Groups A and D2 and the S isomer available commercially for the diagno- of budesonide). Group 2 was defined as halogen- sis of corticosteroid allergies. Of course, ated corticosteroids with a carbon (C) /C don’t wait if you have unanswered ques- 16 17 cis-ketal diol structure (i.e., acetonides from tions. Always feel welcome to contact us because helping you help your patients Coopman Group B) while Group 3 included obtain a diagnosis is the heart of our those halogenated and methylated on C16 mission. (i.e., Coopman Groups C and D1). The poten- cy of corticosteroid patch test substances Kind Regards, has also been ranked from superpotent Dr. Curt Hamann (Class 1) to least potent (Class 7). President & CEO, SmartPractice Why do such classification systems matter? Conceptualizing corticosteroids in these Continued on next page 1 Corticosteroids: A Two-Edged Sword…continued hypothetical classifications has helpful Table 1 Corticosteroid drugs classified by group clinical ramifications. The Coop- Coopman Group Baeck Group Examples man system established that (Structure) (Structure) allergenicity differs across A Cloprednol 1 the groups: Compounds in (Mostly no (Short-chain esters at C21 are Cortisone acetate C methyl Groups A, B, D2 are thought only substitution in D ring) Dichlorisone acetate 16 to be more highly allergen- or halogen Fludrocortisone acetate substitution) ic than those in Groups C Fluorometholone acetate and D1. Furthermore, drugs Fluprednisolone acetate within a group are more Hydrocortisone* likely to elicit cross reactions Isofluprednone acetate than those in different group; Mazipredone however, cross reactions between corticosteroids in differ- Medrysone ent groups (i.e., between budesonide (Group B) and Group Methylprednisone* D2 substances have also been reported. The identification of Prednisolone* potential cross-reacting substances is a crucial step in deter- Prednisone mining alternative products that a patient can use safely (Ta- Tixocortol pivalate ble 1) even though it can be challenging to ascertain whether B 2 (C /C -cis-diol reactions to more than one compound represent true cross (C16/C17-cis-diol or -ketal) 16 17 Amcinonide or -ketal reactions. In general, Group A corticosteroids are considered Halogen to have the potential to cause cross reactions with members substitution**) of Group D2 and with the S isomer of budesonide and vice Budesonide 1 versa. In the Baeck system, patients who react to Groups 2 Desonide 2 and 3 are also likely to react to Group 1. The reverse, how- Fluchloronide ever, does not hold true. Flumoxonide Flunisolide What are the important points to remember when patch test- Fluocinolone acetonide ing patients with corticosteroids? First, patients with chronic Fluocinonide dermatitis that fails to improve after prolonged treatment Halcinonide with corticosteroids are prime candidates for diagnostic patch Triamcinolone 1 testing, especially if their dermatitis deteriorates or spreads. Triamcinolone salts (various) 2 Markers used by the NACDG for testing are tixocortol piva- C Betamethasone 3 (C and halogen late for Group A, budesonide for Group B, desoximetasone (C16 methyl substitution) Desoxymethasone 16 substitution) for Group C, clobetasol-17-propionate for Group D1, and hy- Dexamethasone* drocortisone-17-butyrate for Group D2, all of which are com- Diflucortolone valerate mercially available in petrolatum (or ethanol). The ready-to-use Flumethasone pivalate patch test product includes markers for all groups except the Fluocortin butyl less allergenic Coopman Group C. Fluocortolone* Fluprednidene acetate The concentration of a corticosteroid used for patch testing is Halomethasone important, but the findings may seem counterintuitive: lower Meprednisone doses are associated with a higher frequency of positive reac- D1 Alclomethasone 3 dipropionate (C and halogen tions than higher doses. This tendency is interpreted to indi- (C16 methyl substitution 16 substitution) cate that the anti-inflammatory action of the steroid itself sup- C17/C21 long chain ester) Beclomethasone dipropionate presses an allergic reaction, thereby yielding a false-negative Betamethasone dipropionate reaction. When a patient’s personal corticosteroid product is Clobetasol propionate used for patch testing, it should be remembered that the po- Clobetasone butyrate tency of a corticosteroid can vary depending on its formula- Diflorasone diacetate tion. In other words, the same active ingredient may be more Fluticasone propionate potent in an ointment than in a cream because of differences Mometasone furoate in the rate of penetration. D2 Difluprednate 1 (No methylation or haloge- Hydrocortisone* nation at C16 Doses that are too high have also been associated with the Methylprednisolone C17 long chain ester “edge” effect—an apparent positive reaction confined to the aceponate C21 possible side chain) ring of a round patch test chamber at early readings. Although *Including various salt forms. **Group 2 exceptions to halogen substitution are desonide and halcinonide. 2 Corticosteroids: A Two-Edged Sword…continued an edge effect is considered a negative reaction by strict reading criteria, later readings (day 6 or 7) may show a clear positive reaction at the same site(s). Testing with a lower dose may eliminate the edge effect and yield an early positive reaction. Because of the intrinsic anti-inflammatory effect of corticosteroids, late readings are always advisable. In a Swedish study, for example, the rate of false-negative reactions would have been as high as Now FDA-approved for 30% without late readings. use on patients as young Patients who are suspected of reacting to a corticosteroid should first as 6 years old! undergo patch testing with a baseline screening series. Testing with a marker from all groups may help identify an alternative active ingredient SAME GREAT that patients can use safely if they fall into the monosensitization profile, DIAGNOSTIC, A as did almost 71% of patients in the NACDG study. A patient’s personal WHOLE NEW SET product can be tested, but it is important to be aware that reactions have OF PATIENTS been reported to the vehicle in which some medicinal corticosteroids are formulated. Positive patch test reactions