Korean J Dermatol.  2021 Jun;59(5):379-388.

The Correlations of Minimal Erythema Dose Values with Disease Durations, Contact and Photocontact Allergens and the Effect to Clinical Severity of Chronic Actinic Dermatitis

• Kim JH
• Kim KH

Abstract

Background
Chronic actinic dermatitis (CAD) is an uncommon eczematous photosensitivity disorder having a well-known relationship with allergic or photoallergic contact dermatitis. Moreover, the prognosis of CAD is worse in patients with lower minimal erythema doses (MEDs). However, the correlations between disease duration, contact and photocontact allergens, and MED values in CAD have not been reported.
Objective
To investigate the correlations among MED values, disease duration, and allergic patch/photopatch testing results and to elucidate the correlation between clinical severity and contact/photocontact allergens.
Methods
This study included 121 patients with CAD. Clinical data were analyzed according to the MED values, disease durations, and contact/photocontact allergens. Phototesting and patch/photopatch testing was performed in all the patients.
Results
The MED value was inversely correlated with disease duration for both MED-ultraviolet A and MED-ultraviolet B, with lower MED values for higher numbers of positive items in the patch/photopatch test. The most frequently detected allergens in the patch and photopatch tests were p-phenylenediamine (n=36, 9.3%) and Balsam of Peru (n=29, 21.3%). Clinically, patients demonstrating a greater number of detected allergens show poorer clinical severities (p＜0.05).
Conclusion
The number of contact/photocontact allergens correlates with the severity of CAD.

Keyword

Chronic actinic dermatitis; Patch tests; Photopatch tests