Pityriasis Lichenoides has an unknown etiology and is a skin condition where the patient has a rare type of rash. The rash varies from being chronic and mild to being acute and having severe eruptions. The mild and chronic type is termed as PLC or Pityriasis Lichenoides Chronica and it is characterized by slowly developing scaling papules which are small in size, without other symptoms. These papules flatten out on their own and resolve gradually over the next few weeks. The acute type is termed as Pityriasis Lichenoides Et Varioliformis Acuta or PLEVA and is characterized by sudden development of eruptions of scaling papules which are small in size and turn into blisters then finally crust over resulting in reddish-brown spots.
Treatment comprises of sun exposure, topical and oral steroids, oral antibiotics, topical immunomodulators and phototherapy.
Causes & Risk Factors of Pityriasis Lichenoides
- The exact reason why Pityriasis Lichenoides develops is not known.
- According to experts, this condition can result as a reaction to inflammation from infectious agents.
- This could also occur as result of an immune-related hypersensitivity vasculitis or from a T-cell lymphoproliferative disorder.
- This condition commonly affects adolescents and young adults and often occurs before 30 years of age.
- Men are at a slightly higher risk for developing Pityriasis Lichenoides.
- Infants and elderly are at the least risk for developing this condition.
Signs & Symptoms of PLC or Pityriasis Lichenoides Chronica
- This type is mild in nature and the rashes start to appear slowly over a course of some weeks to months.
- In the beginning, there is development of a small papule which is pink in color.
- This pink papule later changes color to red-brown.
- Often there is a fine scale resembling mica which is adhered to the spot in the middle.
- This scale later peels off resulting in a shiny surface which is pinkish-brown in color beneath the peeled off scale.
- As the weeks pass, the spots flatten out leaving a brownish mark behind.
- This brown mark fades slowly over a period of some months.
- Rashes from different stages can be present at a single time.
- The rashes commonly develop on the arms, trunk, buttocks and legs; however, they can also appear on the face, hands, feet and scalp.
- There is no pain or itchiness in these chronic lesions as opposed to PLEVA lesions.
- Patients suffering from PLC commonly will have flare ups and relapses lasting from months to years.
Signs & Symptoms of PLEVA (Pityriasis Lichenoides Et Varioliformis Acuta)
- Development of red patches, which rapidly turn into papules which are of around 4-15 millimeters in width.
- A fine adherent scale commonly covers these papules.
- There is blood along with pus present in the middle of the papule.
- The papules can erode with development of reddish-brown crust.
- PLEVA lesions commonly develop on the extremities and trunk.
- Sometimes these lesions can be widespread and present on any body parts.
- As opposed to PLC, which is symptomless, PLEVA causes itching and burning sensation in the lesions.
Signs & Symptoms of Febrile Ulceronecrotic Muchas-Habermann
PLEVA has one more subtype which is known as Febrile Ulceronecrotic Muchas-Habermann and it is characterized by necrotic, black colored papules, which quickly transform into large crusted ulcers, pustules and blisters filled with blood, which later merge together. These lesions are often very painful and there is a chance of infection in the ulcers. Febrile Ulceronecrotic Muchas-Habermann if ignored and not treated can be very fatal and can also result in death.
Other Than This, The Patient Also Has Other Symptoms Which Involve Other Systems Such As:
- Sore throat.
- High fever.
- Abdominal pain.
- Lung disease.
- Conjunctival ulcers.
Investigations for Pityriasis Lichenoides
Visual inspection is usually sufficient for diagnosis. A skin biopsy can be done for further confirmation. In skin biopsy a small part or scrapings from the affected region are taken and sent to lab for testing. Other tests which can be done for differential diagnosis include:
- Antistreptolysin O titres.
- HIV screening.
- Cytomegalovirus serology.
- Infectious mononucleosis tests.
- Toxoplasma serology.
- Epstein-Barr virus serology.
Treatment for Pityriasis Lichenoides
If the patient is not experiencing any symptoms with the rash being mild, then treatment is not usually required. Even with acute form of this condition, the patient may not find relief with treatment and continues to have relapses upon discontinuation of treatment.
Generally, Treatment For Pityriasis Lichenoides Comprises Of:
- Limited exposure to sun helps in resolving the lesions.
- Topical steroids can be prescribed for itching and irritation; however, patient should be made aware of the side effects.
- Topical immunomodulators like pimecrolimus and tacrolimus can be applied two times a day to the lesions and are beneficial in resolving the PLC.
- Oral antibiotics can also be used for treating both PLC and PLEVA. The antibiotics commonly used are tetracycline and erythromycin.
- Phototherapy can also be beneficial where the lesions are exposed to artificial UVB / PUVA.
- Oral steroids can be prescribed in more severe cases; however, there are some serious side effects with these.
- Oral and injected Methotrexate has also been beneficial in patients suffering from PLEVA as well as PLC. It is commonly used for treating Febrile Ulceronecrotic Muchas-Habermann.
- For severe cases, where the patient is not responding to any treatment, then the following drugs Acitretin, Dapsone and Cyclosporine can be used in combination.
- Wound care is needed for large ulcers which develop in the Febrile Ulceronecrotic Muchas-Habermann.
- Patient should regularly follow up with their physicians for Pityriasis Lichenoides. This commonly is not a fatal or serious disease; however, rare cases of malignancy have been reported.