Diagnosis
In Pityriasis rosea, the type, intensity, size, numbers and duration of the rash may vary with individuals. In older persons, it may be found in unusual locations, such as the lower body.
Ringworm infections and certain medications, can also invoke reactions that are similar to the rashes caused by PR.
The absence of the herald patch, in some individuals, makes diagnosis difficult. Sometimes the symptoms of PR resemble those of other diseases such as -
- Eczema
- Guttate psoriasis
- Viral exanthem
- Tinea corporis
- Lichen planus
- Pityriasis lichenoides
- Viral exanthem
All these factors make the diagnosis that much more challenging.
A dermatologist may order for the following tests -
- Blood evaluation,
- Scraped skin cells for microscopic exam
- Skin biopsy from the spots/rashes, for microscopic exam
If the diagnosis generates uncertainty in an individual who is sexually active, and if the palms and soles of the feet are affected, the doctor should conduct tests for secondary syphilis, such as,
- VDRL test
- Direct fluorescent antibody testing of lesion exudates,
- Dark-field microscopy.
