What systemic treatment options are recommended for a middle‑aged woman with darker skin and lichen planus pigmentosus limited to sun‑exposed areas who has failed topical therapy?

Systemic Treatment of Lichen Planus Pigmentosus

Direct Recommendation

For a middle-aged woman with darker skin and lichen planus pigmentosus limited to sun-exposed areas who has failed topical therapy, initiate hydroxychloroquine as first-line systemic treatment, with consideration of intramuscular triamcinolone for rapid symptom control. 1

Treatment Algorithm

First-Line Systemic Options

Hydroxychloroquine is the preferred steroid-sparing systemic agent for lichen planus variants, demonstrating a 61% response rate in patients with severe or recalcitrant disease not responsive to topical corticosteroids or calcineurin inhibitors. 1 This medication is particularly appropriate for LPP given the chronic nature of the condition and the need for long-term management without cumulative steroid toxicity.

Intramuscular triamcinolone (IM TAC) achieved the highest treatment success rate at 79% among all systemic therapies for lichen planus, with statistical significance compared to other systemic treatments (P < .01). 1 This can be used as initial therapy or in combination with hydroxychloroquine for faster symptom relief and disease control.

Adjuvant Therapy Considerations

Intralesional triamcinolone (IL TAC) demonstrated 71% success rates and should be considered for localized areas requiring additional treatment to hasten response and symptom relief. 1 This is particularly useful for persistent patches on sun-exposed areas like the face and neck.

Alternative Systemic Options

If hydroxychloroquine and IM TAC fail or are contraindicated:

• Methotrexate showed 42% response rates for extensive lichen planus and is relatively well tolerated. 1, 2
• Oral retinoids are an option for extensive disease with acceptable tolerability profiles. 2
• Narrowband UVB phototherapy can be considered, though caution is warranted due to the risk of koebnerization in lichen planus. 2 Given that LPP occurs in sun-exposed areas and may be triggered by UV exposure, phototherapy should be approached cautiously in this specific variant. 3

Treatments to Avoid

Oral corticosteroids achieved only 24% success rates and should not be used as first-line systemic therapy due to poor efficacy and side effect burden. 1

Dapsone demonstrated only 20% success rates and is not recommended as a primary systemic option. 1

Critical Management Considerations

Trigger Identification and Avoidance

Before initiating systemic therapy, identify and eliminate potential precipitating factors:

• Sun exposure: Critical in LPP affecting sun-exposed areas; strict photoprotection is mandatory. 3
• Contactants: Mustard oil, nickel, henna, paraphenyldiamine, almond oil, amala oil, and cosmetic creams. 3, 4
• Friction: Particularly relevant in intertriginous variants, though less applicable to sun-exposed LPP. 4

Associated Conditions Requiring Screening

LPP has been associated with:

• Hepatitis C virus 3
• Endocrinopathies (diabetes mellitus, hypothyroidism) 3, 4
• Hyperlipidemia 4
• Autoimmune diseases 3

Screen for these conditions as they may influence treatment selection and prognosis.

Common Pitfalls

Relying solely on topical corticosteroids: These are frequently ineffective for LPP pigmentation, though topical tacrolimus may provide some benefit for the dyschromia. 4 However, since this patient has already failed topical therapy, systemic treatment is appropriate.

Delaying systemic therapy: Patients with severe or widespread disease benefit from earlier initiation of systemic therapy to prevent significant morbidity and impact on daily function. 1

Using phototherapy without caution: While narrowband UVB is effective for classic lichen planus, LPP occurs in sun-exposed areas and may be exacerbated by UV exposure, making phototherapy a less ideal choice for this specific variant. 2, 3

Expected Outcomes

Among patients treated with systemic therapy for severe lichen planus: 28% achieved remission, 55% experienced stable disease control, and 17% failed all attempted treatments. 1 Setting realistic expectations is important, as the dyschromia in LPP is frequently refractory to treatment. 4 The goal is to halt the inflammatory process and prevent new pigmentation rather than complete reversal of existing hyperpigmentation.