Indian Dermatology Online Journal

LETTER TO THE EDITOR
Year
: 2016  |  Volume : 7  |  Issue : 6  |  Page : 543--544

Salute sign: A nonambiguous histopathological sign in pityriasis rosea


Mary Thomas, Uday Khopkar 
 Department of Dermatology, Seth Gordhandas Sunderdas Medical College and King Edward Memorial Hospital, Mumbai, Maharashtra, India

Correspondence Address:
Mary Thomas
Department of Dermatology, Seth Gordhandas Sunderdas Medical College and King Edward Memorial Hospital, Mumbai - 400 012, Maharashtra
India




How to cite this article:
Thomas M, Khopkar U. Salute sign: A nonambiguous histopathological sign in pityriasis rosea.Indian Dermatol Online J 2016;7:543-544


How to cite this URL:
Thomas M, Khopkar U. Salute sign: A nonambiguous histopathological sign in pityriasis rosea. Indian Dermatol Online J [serial online] 2016 [cited 2019 Nov 12 ];7:543-544
Available from: http://www.idoj.in/text.asp?2016/7/6/543/193917


Full Text

Sir,

Pityriasis rosea (PR) is a common papulosquamous disorder, characterized by a primary eruption, the herald patch followed by a secondary eruption after 7–14 days.[1] The lesions are characterized by a peripheral collarette of scaling, which is enhanced by dermatoscopy.[2]

The histopathological features of PR were first described by Unna in 1894. Panizon and Block reviewed the histology of 62 patients with PR and proposed four characteristic histological findings, eczematoid pattern (Unna's sign), absence or decrease of granular cell layer (Lowenbach's sign), extravasation of erythrocytes primarily into the papillary dermis and also partly into the epidermis (Sabouraud's sign), and homogenization of the papillary collagen.[3]

The mound of parakeratotic stratum corneum in PR next to or above the spongiotic focus shows separation and elevation from the rest of the stratum corneum on one side, whereas the other side remains attached to the stratum corneum. This parakeratotic scale corresponds to the fine, peripherally attached and centrally detached scales at the edge of the salmon-colored patch/plaque seen in PR, clinically described as the “hanging curtain” sign.[4] This sign is characteristic of PR and can help to differentiate it from other spongiotic dermatoses, especially in atypical cases where the diagnosis is unclear both clinically and histologically [Figure 1].{Figure 1}

This has previously been referred to as the teapot spout sign by some authors due to its resemblance to a teapot spout. Other authors refer to it as the teapot lid sign or just simply the teapot sign.[5] This terminology, comparing the angulated parakeratosis to various parts of a teapot can be quite confusing. We observed that the angulated parakeratosis, which is attached at one end and free on the other end closely resembles a “salute.” Hence we recommend an alternative, simple, and more specific descriptive term for the sign—The salute sign [Figure 2].{Figure 2}

Parakeratotic mounds similar to those in PR are also seen in subacute eczema, eruptive psoriasis, pityriasis lichenoides chronica, and patch-stage mycosis fungoides. However, in subacute eczema, the mounds have globules of plasma in them and are not elevated from the underlying stratum corneum. In eruptive psoriasis, the mounds are commonly topped by collections of pyknotic neutrophils and are frequently embedded within a thicker, orthokeratotic, laminated stratum corneum. In pityriasis lichenoides chronica, the parakeratotic mounds are small and embedded in orthokeratotic stratum corneum. The parakeratotic mounds in patch-stage mycosis fungoides are, as a rule, much more elongated than those in PR.

Although this sign is characteristic of PR, it may rarely be seen in erythema annulare centrifugum.

We recommend the use of a simpler, more descriptive terminology for the angular parakeratotic scale—the salute sign.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Kosuge H, Tanaka-Taya K, Miyoshi H, Amo K, Harada R, Ebihara T, et al. Epidemiological study of human herpesvirus-6 and human herpesvirus-7 in pityriasis rosea. Br J Dermatol 2000;143:795-8.
2Chuh AA. Collarette scaling in pityriasis rosea demonstrated by digital epiluminescence dermatoscopy. Australas J Dermatol 2001;42:288-90.
3Prasad D, Mittal RR, Walia R, Popli R. Pityriasis rosea: A histopathologic study. Indian J Dermatol Venereol Leprol 2000;66:244-6.
4Dhar S, Kanwar AJ, Handa S. 'Hanging curtain' sign in pityriasis rosea. Dermatology 1995;190:252.
5Margo CM, Crowson N, Drysen ME, Mihm CM Jr. The histopathology of eczema. In: Rudikoff DR, Cohen SR, Seheinfeld N, editors. Atopic Dermatitis and Eczematous diseases. 1st ed. Florida CRC press; 2014. p. 289-94.