Mucha-Habermann Disease (Pityriasis Lichenoides et Varioliformis Acuta - PLEVA)
Overview and Clinical Spectrum
Mucha-Habermann disease represents a spectrum of inflammatory skin conditions ranging from mild self-limited eruptions to life-threatening ulceronecrotic disease requiring aggressive immunosuppression. 1
The disease exists along a continuum with three main presentations 1:
- PLEVA (Pityriasis Lichenoides et Varioliformis Acuta): Acute-to-subacute eruption of small red papules evolving into polymorphic lesions with periods of remission, leaving varicella-like scars and pigmentary changes 1
- PLC (Pityriasis Lichenoides Chronica): More gradual onset of small red-to-brown maculopapules with mica-like scale, following a relapsing course with longer remission periods 1, 2
- FUMHD (Febrile Ulceronecrotic Mucha-Habermann Disease): Acute severe generalized eruption of purpuric and ulceronecrotic plaques with systemic involvement and mortality up to 25% 1, 3
Pathophysiology
The etiology remains unclear, with two main theories 1, 4:
- Infectious or drug-related hypersensitivity reaction
- Premycotic lymphoproliferative disorder (T-cell dyscrasia)
Histopathology shows dermal wedge-shaped lymphocytic infiltrate, epidermal spongiosis, parakeratosis, and variable keratinocyte necrosis 1. FUMHD exhibits the most exaggerated histological features 1.
Treatment Algorithm
For PLEVA and PLC (Mild to Moderate Disease)
First-line therapy consists of phototherapy, systemic antibacterials, and topical corticosteroids. 1
Phototherapy options:
- Narrow-band UVB is effective and well-tolerated 1
- PUVA can be used but carries higher long-term carcinogenic risk 5
Systemic antibacterials:
- Tetracyclines or macrolides are commonly employed as first-line agents 1
- The mechanism may involve anti-inflammatory properties rather than antimicrobial effects 1
Topical corticosteroids:
- Potent topical steroids for symptomatic relief of pruritus and inflammation 1
For FUMHD (Severe/Life-Threatening Disease)
FUMHD must be approached as a dermatologic emergency requiring aggressive immunosuppression and intensive supportive care. 1, 3
Methotrexate is the preferred systemic agent:
- Two case reports demonstrated rapid improvement with methotrexate plus antibiotics for superinfection 6
- This represents the strongest evidence for single-agent therapy in severe disease 6
Additional management for FUMHD:
- Intensive supportive care for systemic complications including gastrointestinal involvement, cardiac and hepatic failure 3
- Monitor for macrophage activation syndrome, which can be fatal 3
- Aggressive treatment of superinfection is critical 6
Critical Pitfalls and Caveats
Early diagnosis and aggressive treatment are essential in FUMHD to prevent mortality. 3 The disease can rapidly progress to multi-organ failure with continuous high fever 3.
Distinguish FUMHD from standard PLEVA: Look for large ulcerative necrotic plaques (not just papules), high fever, and systemic symptoms 1, 3. The mortality rate of 25% in FUMHD demands immediate escalation to immunosuppressive therapy 1.
Monitor for progression to cutaneous lymphoma: PLEVA carries potential for lymphomatous transformation, requiring long-term surveillance 1. However, this remains controversial and the true risk is debated 4.
Palmoplantar involvement can mimic psoriasis: Rare presentations of PLC with bilateral palmoplantar lesions may be misdiagnosed, delaying appropriate treatment 2.
Treatment Duration and Monitoring
The disease tends to be self-limited except for FUMHD 4. Treatment for PLEVA/PLC is primarily symptomatic, targeting pruritus relief 4. Continue therapy until lesions resolve, recognizing that relapses are common 1. For phototherapy, typical courses involve 2-3 treatments weekly until clearance 5.