From the Research
Physical Exam Findings of Pityriasis Rosea (PR) Rash
The physical exam findings of a Pityriasis Rosea (PR) rash can vary, but common characteristics include:
- A herald patch, which is an erythematous lesion with an elevated border and depressed center, typically appearing on the trunk 1
- A generalized rash that usually presents two weeks after the herald patch, progressing along the Langer lines to a generalized rash over the trunk and limbs 1
- The rash can be papular, purpuric, vesicular, follicular, or eczematous in nature 2, 3
- The rash can be localized or segmental, and can appear in atypical forms, making diagnosis challenging 2, 3
- Patients can develop general malaise, fatigue, nausea, headaches, joint pain, enlarged lymph nodes, fever, and sore throat before or during the course of the rash 1
Atypical Presentations
Atypical presentations of PR can include:
- Purpuric lesions bilaterally on the legs with classical rash on the trunk 3
- Intensely pruritic and urticarial lesions 3
- Hundreds of small papular lesions 1-3 mm in size 3
- Oral haemorrhagic ulcers with classical PR eruption on the trunk 3
- The herald patch as the only cutaneous manifestation of PR, which can be considered an abortive form of the exanthem 4
Diagnostic Considerations
The diagnosis of PR is based on clinical and physical examination findings, and can be challenging due to the variety of presentations and the possibility of atypical forms 5, 1, 2, 3. Differential diagnoses include secondary syphilis, seborrheic dermatitis, nummular eczema, pityriasis lichenoides chronica, tinea corporis, viral exanthems, lichen planus, and pityriasis rosea-like eruption associated with certain medications 1.