Pityriasis lichenoides chronica (PLC)

Pityriasis lichenoides chronica (PLC) is a rare, benign, inflammatory skin disease, part of the spectrum of pityriasis lichenoides, which also includes the acute form – pityriasis lichenoides et varioliformis acuta (PLEVA). PLC is characterized by a chronic course, the appearance of small, reddish to brownish patches with fine scaling, and often affects children and young adults.
Causes and mechanisms
The exact cause of PLC is unknown. It is thought to be an abnormal immune response to an infectious agent, medication, or antigen from the environment. It is not contagious and is not transmitted from person to person.

Clinical picture
Characteristic manifestations of PLC include:
- Small, flat to slightly raised reddish or brownish papules
- Slight peeling on the surface (dry, fine scales)
- Symmetrically distributed throughout the body – especially on the trunk, upper limbs and thighs
- No severe itching (sometimes mild to moderate)
- Possible hypo- or hyperpigmentation after the lesions disappear

Diagnosis
The diagnosis is made by a dermatologist based on the clinical appearance and confirmed by skin biopsy. Histopathology is key to distinguishing it from other conditions such as:
- lichen planus
- pityriasis rosea
-psoriasis
- cutaneous lymphoma (especially in atypical forms)

Treatment
Treatment is individualized and depends on the severity and duration of the disease. Options include:
- Topical corticosteroids (for limited lesions)
- Calcineurin inhibitors (tacrolimus, pimecrolimus)
- UVB phototherapy (one of the most effective therapies)
- Oral antibiotics (erythromycin, tetracyclines – due to anti-inflammatory effect)
- For resistant forms – methotrexate, immunosuppressants (at the discretion of a dermatologist)
Progress and prognosis
PLC usually has a chronic but benign course. It can last for months to years, with periods of remission and exacerbation. Treatment often does not work. In some cases, complete remission occurs.

Pityriasis lichenoides chronica is a rare but treatable condition. Early diagnosis and appropriate therapy ensure long-term control and minimize cosmetic consequences for the skin.