Case Report

A 40 year-old black woman, coming from Reunion Island (Indian Ocean), presented in July 2010 with a rash on the trunk and upper limbs. She had no allergy and was not taking any medication. She had been treated for a pulmonary embolism 1 year before and for atopic dermatitis as a child. She reported the outbreak of an eruption starting with a single patch on the abdomen followed 5 days later by itchy squamous lesions on the trunk and arms. She had no fever, no viral symptoms within the last weeks. She had had no recent infectious contact and no sexual intercourse except with her husband. No history of sexually transmitted diseases was found. She had experienced dorsal herpes zoster years before and herpes labialis.

Physical examination found multiple centimetric squamous papules on the trunk and arms. All the lesions had a fine vesicular border (Fig. 1); some of the vesicles were umbilicated. Some rosettes were noticed on the trunk and a multiple vesicles scattered on otherwise normal skin. The herald lesion was a 3-centimeter annular patch with central clearance and scaling located on the abdomen under the left breast. There was no lesion on the palms or soles, no mucous membrane or lymph node involvement.

Figure 1

Figure 1. Vesicular pityriasis rosea. (a) Erythematous lesions with a vesicular border, (b) Herald patch on the abdomen.

A 4-millimeter punch biopsy was performed: the epidermis was orthokeratotic with acanthosis, spongiosis and mild exocytosis of lymphocytes and histiocytes. The dermis was edematous with a moderate infiltrate of lymphocytes, histiocytes and rare neutrophils and eosinophils (figure 2). Direct immunofluorescence was negative. A smear of a vesicle fluid was taken for viral culture and was negative for HSV and VZV.

Figure 2

Figure 2. Histological examination, hematoxylin-eosine staining, original magnification x100.

Diagnosis of vesicular pityriasis rosea was made. She was treated with betamethasone 0.05% cream and emollients. Ten days after the beginning of the eruption, she experienced a second rash on the neck and thighs. One month later, the skin lesions were disappearing but were still itchy. The eruption resolved within 6 weeks, with post inflammatory hypopigmentation noted 2 months later.

Discussion

Pityriasis rosea (PR) is a frequent eruption, seen worldwide and at all ages but mainly in children and young adults¹. Diagnosis is usually made when the characteristic herald plaque is found. This initial lesion is followed by a squamous macular or papular eruption of the trunk and proximal limbs, with a Christmas-tree disposition, usually non itchy². Aetiology is probably viral, HHV 6 and 7 have been suspected³. Atypical presentations are described, such as acral PR or with mucosal involvement. Vesicular PR has been reported by Brocq in 1907⁴, 15 cases of vesicular PR were found in literature up to 1927 (table 1).

Figure 3

Table 1. Reported cases of vesicular pityriasis rosea.

Varicella is the first differential diagnosis, as the herald plaque may not have been noticed by the patient and the vesicular rash usually has a descending evolution and can be associated with fever. In our case, the patient had a past history of herpes zoster and negative culture for VZV, excluding varicella. Histological examination and direct immunofluorescence also helped rule out other diagnoses. Our patient was treated with topical steroids as a symptomatic treatment and healed within 6 weeks. This case report highlights the polymorphism of pityriasis rosea. Differential diagnosis, particularly viral eruptions like varicella should be excluded.