To the Editor:
We read with interest the article by Andrachuk et al1 entitled “Linear arrangement of neutrophils along the basal layer in bullous pemphigoid: a unique histological finding” and the Mustasim's reply with interest. We agree with Mutasim that the case of bullous pemphigoid (BP) described in this article could as well be a case of epidermolysis bullosa acquista (EBA) because both may look clinically and histopathologically similar.2 However several important techniques, to differentiate between these 2 entities, were not mentioned in the letter by Mutasim.3
In the first place, differentiation between BP and EBA is possible using direct immunofluorescence microscopy by serration pattern analysis. BP shows an n-serrated linear pattern of immunodeposits along the epidermal basement membrane zone, whereas EBA has a u-serrated pattern.4 Recently, we reported that this pattern recognition was a readily learnable skill.5 We have designed a free accessible website, www.nversusu.umcg.nl, as a learning tool to recognize these patterns.
Fluorescent overlay antigen mapping is another useful technique to differentiate EBA from BP.6 Double staining patient's skin with IgG and a monoclonal antibody against type 7 collagen shows in EBA an overlap of IgG, whereas in BP, IgG staining is just above type 7 collagen.7 Mutatis mutandis double staining with monoclonal antibody against type 17 collagen shows in BP an overlap of IgG, whereas in EBA, IgG staining is just below type 17 collagen.
Finally, when circulating antibodies in patient's serum bound to the dermal side of normal human salt split skin, skin deficient in basement membrane proteins might provide useful information. Particularly, this can be used to differentiate between EBA and anti-laminin-332 mucous membrane pemphigoid.8
In conclusion, the case described by Andrachuk et al1 is not a certain case of BP and needs further investigations according to the above-mentioned algorithm.
1. Andrachuk L, Ghazarian D, Siddha S, et al.. Linear arrangement of neutrophils along the Basal layer in bullous pemphigoid: a unique histological finding. Am J Dermatopathol. 2012;34:192–193.
2. Buijsrogge JJA, Diercks GFH, Pas HH, et al.. The many faces of epidermolysis bullosa acquisita after serration pattern analysis by direct immunofluorescence microscopy. Br J Dermatol. 2011;165:92–98.
3. Mutasim DF. Letter to the editor regarding “linear arrangement of neutrophils along the basal layer in bullous pemphigoid: a unique histological finding”. Am J Dermatopathol. 2013;35:287.
4. Vodegel RM, Jonkman MF, Pas HH, et al.. U-serrated immunodeposition pattern differentiates type VII collagen targeting bullous diseases from other subepidermal bullous autoimmune diseases. Br J Dermatol. 2004;151:112–118.
5. Terra JB, Meijer JM, Jonkman MF, et al.. The n- versus u-serration is a learnable criterion to differentiate pemphigoid from epidermolysis bullosa acquisita in direct immunofluorescence serration pattern analysis. Br J Dermatol. 2013;169:100–105.
6. Bruins S, de Jong M, Heeres K, et al.. The differentiation of bullous pemphigoid and epidermolysis bullosa acquisita by fluorescence overlay antigen mapping. J Invest Dermatol. 1995;105:509–9.
7. de Jong MCJM, Bruins S, Heeres K, et al.. Bullous pemphigoid and epidermolysis bullosa acquisita: differentiation by fluorescence overlay antigen mapping. Arch Dermatol. 1996;132:151–157.
8. Terra JB, Pas HH, Hertl M, et al.. Immunofluorescence serration pattern analysis as a diagnostic criterion in antilaminin-332 mucous membrane pemphigoid: immunopathological findings and clinical experience in 10 Dutch patients. Br J Dermatol. 2011;165:815–822.