[Hand eczema or psoriasis: update on the FB 323 study occupational dermatology cohort]

In daily dermatological practice, the distinction between eczema and psoriasis in dermatoses of the hands can be difficult. However, a clear diagnosis is necessary to initiate optimal therapy and management. In recent years, the so-called molecular classifier has been developed for optimized differentiation of eczema and psoriasis. An occupational dermatological cohort has been established at Heidelberg University Hospital since 2020. It is funded by the German Statutory Accident Insurance. The aim is to follow-up patients over 3 years where this new diagnostic method is used and to compare the results with a retrospective occupational dermatological cohort. Recruitment ended in December 2022. The current analysis reports participants' occupational activity, insurance status, disease progression, and number of sick days. A total of 287 patients were included; mean age was 50.4 years and 63.5% (n = 181) were undergoing treatment at the expense of the liable statutory accident insurance at the start of the study. About 50% of the patients worked in health professions, metal industry, or construction. The average duration of occupational dermatosis was 6.5 years. In 38.9% of the patients, the clinical diagnosis had been classified as unclear by the treating dermatologist. By using the molecular classifier, the diagnosis could be clarified in 98% of the cases (eczema vs. psoriasis). The first analyses demonstrate that the molecular classifier contributes to improving therapy by optimizing the diagnosis.

A negative breakdown test in a fragrance mix I-positive patient does not rule out contact allergy to its fragrance constituents

BACKGROUND

In about half of the patients reacting positive to fragrance mix I (FM I), breakdown testing remains negative. This raises the question of whether the reaction to FM I is false-positive, or the breakdown test is false-negative.

OBJECTIVES

To identify characteristics and sensitization patterns of patients positive to FM I, but not to its fragrance constituents.

PATIENTS AND METHODS

Retrospective analysis of data from the Information Network of Departments of Dermatology (IVDK) between 2005 and 2019. Three patient groups were defined according to their reaction pattern: Group I, FM I positive and ≥1 single fragrance positive in the breakdown test (n = 1912); Group II, FM I positive and breakdown test negative (n = 1318); Group III, FM I negative (n = 19 790).

RESULTS

Regarding the pattern of concomitant reactions to other fragrances, Group II had an intermediate position between Group I and Group III. In other respects (age and sex distribution, frequency of sensitization to non-fragrance baseline series allergens), Group II rather resembled Group I.

CONCLUSIONS

Not every positive reaction to FM I in patients with negative breakdown tests is false-positive. There may be false-negative reactions to the single fragrance components when patch tested at 1% pet. Raising patch concentrations of some single fragrances is recommended.

Atopy patch testing with aeroallergens in a large clinical population of dermatitis patients in Germany and Switzerland, 2000-2015: a retrospective multicentre study

BACKGROUND

The diagnostic significance of the atopy patch test for the management of dermatitis possibly triggered by aeroallergens is still controversial. However, sufficiently large studies with routinely tested standardized aeroallergen patch test preparations in dermatitis patients are lacking.

OBJECTIVE

To evaluate the reaction frequency and the reaction profiles of 10 until mid-2015 commercially available, standardized aeroallergen patch test preparations of the 'Stallerpatch' test series (Stallergenes, Antony Cedex, France) in a large multicentre patient cohort.

METHODS

A retrospective data analysis of patients with suspected aeroallergen-dependent eczematous skin lesions was performed, who were patch tested in 15 Information Network of Departments of Dermatology-associated clinics between 2000 and 2015. Patients were stratified according to their atopic dermatitis (AD) status.

RESULTS

The study group included 3676 patients (median age 41 years, 34.8% males, 54.5% AD). The most common aeroallergens causing positive patch test reactions were Dermatophagoides pteronyssinus (19.6%), Dermatophagoides farinae (16.9%), birch (6.2%), timothy grass (6.0%), cat dander (5.4%), mugwort (4.9%) and dog dander (4.6%). Reactions to other pollen allergen preparations, that is 5 grasses (3.2%), cocksfoot (2.1%) and plantain (1.6%), were less common. Positive patch test reactions to aeroallergens were consistently more frequent in patients with AD. These patients showed proportionally less dubious, follicular, irritant and weak positive reactions. Independent of AD status, a patient history of past or present allergic rhinitis was associated with an increased chance of a positive aeroallergen patch test reaction to pollen allergens.

CONCLUSION

The aeroallergen patch test is a useful add-on tool in clinical routine, especially in patients with AD and/or respiratory allergy. A patch test series comprising Dermatophagoides pteronyssinus, Dermatophagoides farinae, birch, timothy grass, cat dander and mugwort seems to be suitable. Controlled studies with specific provocation and elimination procedures are required to further evaluate the diagnostic significance of the proposed screening series.

A variant of the CXCL11 gene may influence susceptibility to contact allergy, particularly in polysensitized patients

BACKGROUND

Hereditary factors may influence individual susceptibility to contact allergy.

OBJECTIVES

To investigate genetic variants with impacts on early inflammatory reactions and T cell functions that possibly increase the risk of contact allergy.

PATIENTS AND METHODS

Three hundred and seventy two patients undergoing patch testing were recruited from the Information Network of Departments of Dermatology (IVDK). Of these, 133 were monosensitized and 239 were polysensitized, defined as reacting to three or more unrelated sensitizers. Within the polysensitized individuals, a subgroup with at least one particularly strong patch test reaction (strong reactors; n = 194) was considered. Three hundred and forty-seven blood bank donors served as controls. Fifteen genetic variants in 13 genes were analysed.

RESULTS

The homozygous variant CXCL11 AA genotype (rs6817952) was significantly more frequent among polysensitized patients (10 of 239 = 4.2%; p = 0.0048; odds ratio 7.49; 95%CI: 1.7-36.1) than among monosensitized patients (2.2%) and in the control group (0.6%). None of the remaining genetic variants investigated were characterized by similarly strong associations. However, the significance was lost after correction for multiple comparisons.

CONCLUSIONS

The homozygous variant CXCL11 genotype is associated with an increased risk of contact allergy. To confirm this exploratory finding, further independent studies are needed.