Pityriasis Rosea Clinical Presentation

The history should include questions about close contacts with similar eruptions. This finding is uncommon because most cases of pityriasis rosea are sporadic, as pityriasis rosea is thought to reflect a weakly contagious disease. A history of medication intake should be obtained because several medications have been shown to cause a similar exanthem.

• The disease typically begins with a solitary macule that heralds the eruption (called the herald spot/patch), which is usually a salmon-colored macule. This initial lesion enlarges over a few days to become a patch with a collarette of fine scale just inside the well-demarcated border.
• Within the next 1-2 weeks, a generalized exanthem usually appears, although it may occur from hours to months after the herald patch. This secondary phase consists of bilateral and symmetric macules with a collarette scale oriented with their long axes along cleavage lines. This phase tends to resolve over the next 6 weeks, but variability is common.
• Pruritus is common, usually of mild-to-moderate severity, and it occurs in 75% of patients.

• The herald patch is usually a single pink patch, 2-10 cm in diameter, on the neck or the trunk with a fine collarette scale (see following image). It is observed in more than 50% of patients, and it may occur as multiple lesions or in atypical locations. Herald patch. Courtesy of the Drexel Department of Dermatology slide collection.
• About 1-2 weeks after the herald patch is seen, the generalized eruption appears, although it has been known to occur from hours to 3 months later. It consists of salmon-colored macules or patches, 0.5-1.5 cm in diameter, with a collarette scale, often described as having a cigarette paper–like appearance. The long axes of the lesions are oriented in a parallel fashion along cleavage lines, giving the classic Christmas tree pattern (see following image). These secondary lesions most commonly occur on the trunk, the abdomen, the back, and the proximal upper extremities. Christmas tree distribution of lesions on the trunk. Courtesy of the Drexel Department of Dermatology slide collection.
• Pruritus occurs in 75% of patients and is severe in 25%.
• Lymphadenopathy is uncommon, but, when present, it is usually observed in African Americans.
• Atypical pityriasis rosea occurs in 20% of patients.

  • These variations can be separated into changes in the lesions and/or their distribution. Variable distribution can be difficult to evaluate.
  • Photosensitivity may occur. Photoexacerbated and photoprotected forms have been documented, although photosensitivity is not a classic manifestation of the disease.
  • Lesions may be localized to single areas, such as the abdomen, the groin, the axilla, the distal extremities, the palms, and the soles.
• An inverse pityriasis rosea may be seen. This form manifests as lesions on the face and the distal extremities, and it is more common in children than in adults. The herald patch may be the only manifestation of the disease.
• A unilateral variant in which the lesions do not cross the midline has been described.
• Drug-induced cases are frequently observed without the herald patch.
• Variations in lesion morphology are noteworthy.

  • Atypical, large patches tend to be fewer in number. They may coalesce to form a variant known as pityriasis circinata et marginata of Vidal. The primary lesions may be papules, vesicles, pustules, or urticarial or purpuric plaques. Pityriasis rosea may first be evident with widespread, intensely pruritic papulovesicles in an unusual distribution, such as on the neck and the scalp.
  • Papular pityriasis rosea tends to have scaling papules in the normal distribution; this form is more common in children than in adults.
  • Erythema multiforme–like plaques may be evident.
  • Oral involvement may occur as punctate hemorrhages, ulcers, papulovesicles, bullae, or erythematous plaques. Most studies find the incidence to be less than 10%; however, one study reported them in as many as 16% of patients.
  • Purpuric pityriasis rosea is seen in both adults and children, and it follows the usual presentation of the disease.
  • African American children may have more frequent papular lesions and facial and scalp involvement than is usually described. Also of interest is that many patients have resolution of lesions within 2 weeks.^[7]

Pityriasis rosea may represent a viral exanthem (and at times enanthem).

• Pityriasis rosea–like drug eruptions may be difficult to distinguish from non–drug-induced cases. Medication-induced eruptions have been reported with captopril, metronidazole, isotretinoin, penicillamine, levamisole, bismuth, gold, barbiturates, ketotifen, clonidine, aspirin, and omeprazole. A single case has been reported with terbinafine. Imatinib mesylate and etanercept have also been implicated.
• Certain vaccinations, such as the BCG vaccine or the diphtheria vaccine, have been reported to cause similar eruptions.
• Lesions are also thought to be increased in individuals with high stress levels.