Transient Acantholytic Dermatosis: New Dermatoscopic Features.

Dear Sir,

Transient acantholytic dermatosis (TAD) is a nonfamilial and nonimmunological acantholytic disorder.[1] Here, we present a case of TAD manifesting dermatoscopic findings not described before.

A 63-year-old male presented with a 3-month history of severely itchy skin lesions. Dermatologic examination revealed excoriated erythematous papules of 1-3 mm, with tiny hemorrhagic crusts, localized mainly on the upper back and chest [Figure 1a and b]. Dermatoscopy (DermLite DL IV, polarized, ×10) showed peripheral grayish-brown crusts, forming full or partial round, ovoid, or triangular-like borders. At some lesions, white scales were present over these crusts, which sometimes extended to or covered the central areas. There were whitish-pink or red homogenous areas surrounding the crusts, with a few dotted vessels [Figure 2a–f].

Figure 1

(a and b) Erythematous papules with small central crusts

Figure 2

(a and b) Grayish-brown crusts forming full or partial circles with superimposed white scales. (c) Peripheral crust presenting a triangular shape. (d) White scales occluding the circle. (e and f) Whitish-pink/red homogenous areas surrounding crusts, with a few dotted vessels

Two punch biopsies were performed. Both of them showed parakeratosis, dyskeratotic cells, small foci of acantholytic clefts, and mild perivascular inflammation in the upper dermis. One biopsy also showed a parakeratotic column overlying a suprabasal acantholytic cleft and spongiosis [Figure 3a and b].

Figure 3

(a) Hailey–Hailey subtype: parakeratosis, dyskeratotic cells, suprabasal clefts, and perivascular mild inflammation (HE, ×100). (b) Darier subtype: parakeratotic column, suprabasal cleft, dyskeratotic cells, spongiosis, and upper dermal inflammation (HE, ×100)

Discussion

TAD is characterized histologically by suprabasal acantholysis, with or without dyskeratosis. Eczematous features and lymphohistiocytic perivascular infiltrate can also be observed. Four classic histopathologic patterns are recognized: darier like, pemphigus vulgaris like, Hailey–Hailey like, and spongiotic.[1]

Till date, only a few reports have been published on the dermatoscopic features of TAD[234567] [Table 1].

Table 1

Reports on the dermatoscopicC features of TAD

Reference	Number of cases	Dermatoscopic Features	Histopathologic variant
Giacomel et al.[6]	1	Micro-fissures and scales forming tan/brown star-like shape	Darier like
		Fine hairpin vessels with white halos on a pinkish background
Sadayasu et al.[2]	1	Irregular yellow-brown crypts edged with white band-like areas	Darier like
Errichetti et al.[3]	7	Central branched, polygonal, or round-brownish areas surrounded by whitish halo	3 Darier like
			4 Spongiotic
		Whitish scales over a reddish-yellow background
		Subtle dotted and telangiectatic vessels
Fink et al.[5]	2	Central yellowish-brown erosion with a stellar, polygonal, or round shape, surrounded by whitish-pink area with dotted linear vessels	Darier like
de Abreu et al.[4]	1	Early lesion: pinkish-white background, central glomerular, peripheral linear, and hairpin vessels	Darier-like
		Late lesion: central yellowish to brown star-like pattern, white radiating halo
Lacarrubba et al.[7]	1	Polygonal, star-like yellowish/brownish areas, surrounded by white thin halos	Darier like

A case reported by Sadayasu et al.[2] showed irregular yellow to brown crypts edged with white band-like areas, surrounded by an erythematous halo, and whitish scaly areas in the brown crypts. The authors suggested that the star-like pattern corresponds to parakeratosis, while the white bands correspond to ortho-hyperkeratosis.

In another case report, while Darier-like subtype manifested a central star-like or roundish-oval brownish area surrounded by a whitish halo, spongiotic subtype displayed whitish scales over a reddish-yellowish background.[3] However, as different subtypes of TAD may be seen in combination in a given lesion,[1] the correlation of dermatoscopic pattern with histopathologic subtype may not be strict.

Our first biopsy was consistent with Hailey–Hailey, and the second with Darier subtype. Though our patient displayed roundish-oval shapes, there was no star-like structure. We also saw white scales on brownish-pinkish ground, but they were mainly superimposed on peripheral brownish-gray, crusty borders.

de Abreu et al.[4] described the dermatoscopic features of early vs late lesions of TAD. Early lesions, defined as erythematous papules, displayed pinkish-white background and central glomerular, peripheral linear/hairpin vessels. Late lesions, defined as crusted papules, showed a central yellowish-brown, star-like pattern surrounded by a white radiating halo, with hairpin and linear vessels. However, as the lesions of TAD can easily be excoriated due to intense itching, crusts may not always indicate lesion age.

The most striking feature of our patient was brownish-gray, prominent border with scale crusts. The dermatoscopic differential diagnosis of macules with peripheral scale crusts includes porokeratosis and pityriasis rosea. Porokeratosis shows an annular structure with a central whitish to hyperpigmented area and a peripheral yellowish-white, often double-marginated border, defined as “white track.” Brownish dots, globules, and open pores with plugs, in addition to dotted and hairpin vessels are other described features.[8] In our patient, the lesions showed peripheral grayish-brown scales without double border phenomenon. The central area was not hypo- or hyperpigmented and no brown globules or dots were present. On the other hand, pityriasis rosea shows peripheral white scales and yellowish-orange background.[9] In our patient, the lesions were mainly rimmed by dark scale crusts, and white scale was a component that was partially present over or inside of the border. We think that besides dyskeratosis, parakeratosis may be responsible for this manifestation; nevertheless, the underlying factors are not totally clear yet.

In conclusion, the dermatoscopic features may not show the previously described features for TAD in every case, and dermatologists should preserve the suspicion of TAD if clinical features suggest so and should confirm the diagnosis by histopathologic examination. We underline that even though grayish-brown crusty frame-like borders with superimposed white scales, as seen in the present case, may be considered as nonspesific, they may support the diagnosis of TAD if clinical features are compatible.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.