Contact Dermatitis

Contact Allergy to Topical Medicaments, Part 2: Steroids, Immunomodulators, and Anesthetics, Oh My!

Author and Disclosure Information

Topical drugs are used to treat a variety of cutaneous and noncutaneous conditions. Direct application to the skin can result in adverse cutaneous effects, including allergic contact dermatitis (ACD). In part 2 of this series on topical medicament ACD, we focus on corticosteroids, immunomodulators, and anesthetics.

Practice Points

  • Allergic contact dermatitis (ACD) should be suspected in patients with persistent or worsening dermatitis after use of topical medications.
  • Cross-reactions commonly occur between structurally similar compounds and occasionally between molecules from different drug classes.
  • Some cases of topical medicament ACD remain elusive after patch testing, particularly drugs with potent immunomodulating effects.



In the first part of this 2-part series (Cutis. 2021;108:271-275), we discussed topical medicament allergic contact dermatitis (ACD) from acne and rosacea medications, antimicrobials, antihistamines, and topical pain preparations. In part 2 of this series, we focus on topical corticosteroids, immunomodulators, and anesthetics.


Given their anti-inflammatory and immune-modulating effects, topical corticosteroids are utilized for the treatment of contact dermatitis and yet also are frequent culprits of ACD. The North American Contact Dermatitis Group (NACDG) demonstrated a 4% frequency of positive patch tests to at least one corticosteroid from 2007 to 2014; the relevant allergens were tixocortol pivalate (TP)(2.3%), budesonide (0.9%), hydrocortisone-17-butyrate (0.4%), clobetasol-17-propionate (0.3%), and desoximetasone (0.2%).1 Corticosteroid contact allergy can be difficult to recognize and may present as a flare of the underlying condition being treated. Clinically, these rashes may demonstrate an edge effect, characterized by pronounced dermatitis adjacent to and surrounding the treatment area due to concentrated anti-inflammatory effects in the center.

Traditionally, corticosteroids are divided into 4 basic structural groups—classes A, B, C, and D—based on the Coopman et al2 classification (Table). The class D corticosteroids were further subdivided into classes D1, defined by C16-methyl substitution and halogenation of the B ring, and D2, which lacks the aforementioned substitutions.4 However, more recently Baeck et al5 simplified this classification into 3 main groups of steroids based on molecular modeling in combination with patch test results. Group 1 combines the nonmethylated and (mostly) nonhalogenated class A and D2 molecules plus budesonide; group 2 accounts for some halogenated class B molecules with the C16, C17 cis ketal or diol structure; and group 3 includes halogenated and C16-methylated molecules from classes C and D1.4 For the purposes of this review, discussion of classes A through D refers to the Coopman et al2 classification, and groups 1 through 3 refers to Baeck et al.5

Class A–D Corticosteroid Classification System

Tixocortol pivalate is used as a surrogate marker for hydrocortisone allergy and other class A corticosteroids and is part of the group 1 steroid classification. Interestingly, patients with TP-positive patch tests may not exhibit signs or symptoms of ACD from the use of hydrocortisone products. Repeat open application testing (ROAT) or provocative use testing may elicit a positive response in these patients, especially with the use of hydrocortisone cream (vs ointment), likely due to greater transepidermal penetration.6 There is little consensus on the optimal concentration of TP for patch testing. Although TP 1% often is recommended, studies have shown mixed findings of notable differences between high (1% petrolatum) and low (0.1% petrolatum) concentrations of TP.7,8

Budesonide also is part of group 1 and is a marker for contact allergy to class B corticosteroids, such as triamcinolone and fluocinonide. Cross-reactions between budesonide and other corticosteroids traditionally classified as group B may be explained by structural similarities, whereas cross-reactions with certain class D corticosteroids, such as hydrocortisone-17-butyrate, may be better explained by the diastereomer composition of budesonide.9,10 In a European study, budesonide 0.01% and TP 0.1% included in the European Baseline Series detected 85% (23/27) of cases of corticosteroid allergies.11 Use of inhaled budesonide can provoke recall dermatitis and therefore should be avoided in allergic patients.12

Testing for ACD to topical steroids is complex, as the potent anti-inflammatory properties of these medications can complicate results. Selecting the appropriate test, vehicle, and concentration can help avoid false negatives. Although intradermal testing previously was thought to be superior to patch testing in detecting topical corticosteroid contact allergy, newer data have demonstrated strong concordance between the two methods.13,14 The risk for skin atrophy, particularly with the use of suspensions, limits the use of intradermal testing.14 An ethanol vehicle is recommended for patch testing, except when testing with TP or budesonide when petrolatum provides greater corticosteroid stability.14-16 An irritant pattern or a rim effect on patch testing often is considered positive when testing corticosteroids, as the effect of the steroid itself can diminish a positive reaction. As a result, 0.1% dilutions sometimes are favored over 1% test concentrations.14,15,17 Late readings (>7 days) may be necessary to detect positive reactions in both adults and children.18,19

The authors (M.R., A.R.A.) find these varied classifications of steroids daunting (and somewhat confusing!). In general, when ACD to topical steroids is suspected, in addition to standard patch testing with a corticosteroid series, ROAT of the suspected steroid may be necessary, as the rules of steroid classification may not be reproducible in the real world. For patients with only corticosteroid allergy, calcineurin inhibitors are a safe alternative.


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