Case Number : Case 2781- 4 March 2021 Posted By: Saleem Taibjee

The history would immediately suggest a diagnosis of dermatitis herpetiformis but the histology does not support that diagnosis.  The intense itch, stratum corneum pustule formation, upper dermal purpura (probably artefactual from scratching) and eosinophils in the infiltrate call for deeper sections.  I think these might reveal the scabies mite, although it depends from what site the biopsy was taken whether the mite will reveal itself!

not all of the initial images were included, hence also see below:

Prebullous stage of pemphigoid is a possibility which needs confirmation by IF study. 

We need IF for sure but I´m thinking in Scabies.

There was a similar case posted by Saleem in July 2020 (case 2611) which prompted a discussion on differential diagnosis.  For me, I am put off a diagnosis of bullous pemphigoid for several reasons.   The rather loose inflammatory infiltrate is not particularly interested in the basement membrane zone, and the stratum corneum changes wouldn't be expected in pemphigoid.  Also the anatomical distribution of the symptoms don't suggest pemphigoid either.  My money remains on scabies.

I might lose it all of course!

Why not an eosinophilic rich DH? After all, the cellular infiltrate contains many neutrophils and more than one dermal papillae seem affected. 

shall think of prebullous phase of BP DIF needed

I am not aware of DH with eosinophils

Thanks for the comments.

This is Dermatitis Herpetiformis. As Richard notes, the clinical distribution is absolutely typical.

The direct immunofluorescence (performed at the St John's Institute of Dermatology) showed bright granular deposition of IgA in the dermal papillae. A beautiful image of the IMF in this case is shown below, gratefully provided by John Mee and Richard Groves.

The eosinophils have understandably thrown many, but it shows the variation to be aware of in DH, and is in fact previously described in the literature as well as some of the textbooks. Richard Groves also confirms that he has seen some cases of DH with numerous eosinophils.

I deliberately did not show the histology of the second biopsy from the patient (now shown below), in which in addition to notable eosinophils, also highlighted some foci of more convincing papillary microabscesses containing neutrophils.

BW

Saleem

Thanks Saleem - I was not aware that DH could have so many eosinophils.  Vincenzo is vindicated, and I lost my money on the mite!

Thanks, Richard. but my pockets are almost empty because of the many times I’m losing. 

I hadn't realised that I was promoting gambling. Still ... there are worse things to gamble on.

Thanks Dr

Interesting case!