Is there a histopathologic difference between palmar psoriasis and hand eczema?
There is a marked difference in the thickness of the granular layer between palmar psoriasis and hand eczema, and this may be helpful in differentiating between the two skin conditions, according to a recent study.
Additionally, no significant difference exists between palmar psoriasis and hyperkeratotic hand dermatitis (HHD).
Researchers sought to distinguish the histopathologic differences among palmar psoriasis, hand eczema and HHD, which have been poorly characterized. They conducted a retrospective analysis of the histology of hematoxylin-eosin‒stained sections obtained from patients (n=96) with palmar psoriasis, hand eczema or HHD.
The participants were divided into four subgroups: palmar psoriasis (n=16; group A), hand eczema without atopic or nummular dermatitis (n=41; group B), hand eczema with atopic or nummular dermatitis (n=14; group C), and HHD (n=25; group D).
Patients diagnosed with palmar psoriasis (p=0.047) had a more consistent loss of the granular layer (group A, 62.5 percent; group B, 24.4 percent; group C, 0 percent) than hand eczema patients (p=0.002). Psoriasiform epidermal hyperplasia (group B, 36.6 percent; group C, 35.7 percent; group D, 72.0 percent) favoured a diagnosis of HHD (p=0.01) over hand eczema (p=0.043).
This study is limited by its retrospective design and small sample size, according to researchers.
A previous study reported that the relationship between clinical type of hand eczema and aetiological diagnosis fitted with general experience, but there was no simple relationship observed, emphasizing that patch testing and exposure analysis are mandatory. Furthermore, researchers identified hyperkeratotic palmar hand eczema as a distinct clinical subtype. [Contact Dermatitis 2011;65:13-21]