Approach

There is no standard therapy for pityriasis lichenoides and there is minimal high-quality evidence for the different treatment options.[1][25]​​ The best approach to managing pityriasis lichenoides is with combination therapy: use of corticosteroids, tacrolimus, phototherapy, antimicrobials or systemic therapy (in recalcitrant disease).

Initial treatment for most cases of pityriasis lichenoides is a topical approach with corticosteroids, or a topical immunomodulator.[4] Due to the documented efficacy of ultraviolet (UV) phototherapy, one systematic review suggests that narrowband ultraviolet B (UVB) phototherapy could be considered as first line therapy.[25]

If the clinician suspects medication as a potential culprit to pityriasis lichenoides, discontinuation of this medication is a logical solution.

Topical corticosteroids, immunomodulators, and oral antihistamines

Topical application of corticosteroids or immunomodulators, such as tacrolimus, is useful to alleviate acute inflammation and pruritus. General skin emollients can be useful for occasional xerosis. Oral antihistamines may be tried adjunctively to reduce symptoms of pruritus and burning.[1] However, some experts believe they are not effective. Cetirizine is a second-generation minimally sedating H1-antagonist that can be administered to adults and children.

These treatments do not alter the course of this skin disease.[1]

Phototherapy

Phototherapy is regarded as an effective treatment option for pityriasis lichenoides.[1][26]​​[27]​ It can be used if there is no response to the first line treatment. It is utilized by various methods including broadband UVB, narrowband UVB, psoralen and UVA (PUVA), and UVA1. Light therapy, especially narrowband UVB, has shown exceptional therapeutic value, tolerance, and safety.[4] The mechanism of action of phototherapy for pityriasis lichenoides is unknown. It is likely that the immune-modulating effects of ultraviolet radiation serve an important function to alleviate this skin condition. It is difficult to select the most appropriate method of phototherapy for pityriasis lichenoides because of reported variability. Narrowband UVB is a favored therapy in clinical practice.​[26][28]

Antimicrobial therapy

If the suspected trigger is a known infective pathogen, antimicrobial therapy targeting that pathogen is the optimal treatment choice. Some studies support the use of antimicrobials regardless of the trigger.[26]​ Antimicrobials, such as tetracycline, doxycycline, and erythromycin have shown utility in pityriasis lichenoides.[1][4]​ These agents may be especially advantageous in pityriasis lichenoides due to their anti-inflammatory properties.[4] Azithromycin is another antimicrobial option; one study found that azithromycin was comparable to narrowband UVB in terms of treatment efficacy among patients with pityriasis lichenoides chronica.[6]​ A gradual taper of these antibiotics is also advised to avoid disease recurrences. Erythromycin is a better choice in the pediatric population, due to the possible dental side effects linked to tetracycline.

Treatment-resistant and severe disease

Severe disease includes patients with medium-to-large lesions, pruritic or painful lesions, and those associated with constitutional symptoms. Patients with severe disease should be seen by a dermatologist and treated with systemic medications such as corticosteroids, methotrexate, ergocalciferol, pentoxifylline, dapsone, immune globulin, and retinoids.[1][4][29]​ Systemic corticosteroids should be considered in the treatment of pityriasis lichenoides with a relentless and chronic course, as well as concurrent constitutional symptoms such as fever, arthritis, and myalgias. The majority of these systemic immunosuppressive agents are not suitable for the pityriasis lichenoides pediatric-predominant population, so appropriate vigilance has to be implemented on the rare occasions these medications are administered.

High-dose immunosuppressive therapy with intensive and supportive care is required to manage the febrile ulceronecrotic Mucha-Habermann disease variant of the disease. There are a few reports of effective treatment of this variant with a methotrexate and high-dose corticosteroid combination and with cyclosporine.[4][23][26]​ Fulminant febrile ulceronecrotic Mucha-Habermann disease pityriasis lichenoides should be managed as a dermatologic emergency because it usually requires acute hospital care and intensive or burn unit monitoring, with proper wound care of the necrotic skin lesions. 

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