Multiple coalescing Herald patches.

Sir,

Pityriasis rosea is a self-limiting asymptomatic skin eruption that begins with a Herald patch followed in several days to weeks by multiple similar smaller lesions along the cleavage of trunk (Christmas tree pattern). It was first described by the famous Edinburgh dermatologist Robert Willan by another term in 1798. The term “Pityriasis rosea” was first used by Gilbert in1860 and means pink (Rosea) scales (Pityriasis).

A 10-year-old girl was brought to our outpatient department by her mother with complaints of asymptomatic skin lesions over abdomen which started 10 days back. Three plaques, two in the left lower abdomen and one over right lower abdomen were initially noted. All the plaques were gradually progressive in nature. Six days after the eruption of primary lesions, secondary plaques started erupting over abdomen and back. There was no history of similar complaints in the family. There was no fever prior to the evolution of lesions or any history suggestive of prior upper respiratory tract infection. The child was not on any drug prior to the onset of eruption.

Dermatological examination showed three primary lesions (mother patches) out of which two of twowere coalescing with each other [Figures 1 and 2]. The lesions were well defined, erythematous, and nearly ovalin shape with a typical collarette of scales at the margin.Secondary eruptions were oval, few in number, involving lower part of abdomen and back with peripheral scaling. Oral and genital mucosa, palms and soles, face, groin, axillae were examined and they were normal.

Figure 1

Multiple Herald patches with secondary patch

Figure 2

Coalescing Herald patches

Histopathological examination was not done since it is nonspecific in this condition and the patient was a child. Apart from typical manifestations of Pityriasis rosea with Herald and secondary patches, clinical picture may be different in about 20% cases, especially in children and young adults.[1] Atypical cases of PR may involve face, flexures, mucosa and palm-soles.[1] Hips and shoulders are predominantly affected in limb girdle PR.[2] Sometimes PR may be unilateral, inverse, papular, vesicular, lichenoid, or hemorrhagic.[1] Facial and scalp involvement, papular lesions and post inflammatory disorder of pigmentation have been reported in black patients.[3] PR with severe pruritus, burning sensation, and pain is known as PR irritata. PR with enormous plaque is known as Pityriasis rosea gigantea of Darier. In cases of papular PR, the lesions are very small.[2] Sometimes primary plaque may be the only manifestation. Occasionally secondary rash may be exclusively peripheral in nature. In this case, it is known as PR inversa. In the case of PR gigantea, lesions are few in number, usually develop in the vicinity of the primary plaque and is usually confined to the trunk. Lesions may be circinate and at times confluent, persisting for months (Pityriasis Circinata et Marginata of Vidal).[4]

We are reporting this case due to occurrence of multiple mother patches and their coalescence, which is a very unusual presentation of a very common disease. We suggest that this is Pityriasis Circinata et Marginata of Vidal.