Pityriasis lichenoides (et varioliformis) acuta L41.0

Mucha, 1916; Habermann, 1925

Often triggered by infectious allergies, inflammatory, self-limited, multiform disease with acute course, with preferential occurrence in the autumn and winter months. About 50% of the patients suffer from pruritus.

Many authors consider pityriasis lichenoides et varioliformis acuta as an acute course form of pityriasis lichenoides, so it can be assumed that they are different acute stages of one and the same entity.

Transitional forms between pityriasis lichenoides et varioliformis acuta (PLEVA) and pityriasis lichenoides chronica (PLC) are possible. They are about 5% in larger collectives.

An extremely rare variant of PLEVA (50 cases in the literature to date) is considered to be the highly febrile ulceronecrotic course (pityriasis lichenoides with ulcers and hyperthermia = PLUH), which is associated with severe morbidity. Another name for this variant is FUMHD.

Incidence is 1:6000/1:12,000

Unknown (immune complex vasculitis?).

Both PLC and PLEVA are lymphoproliferative T-cell disorders.

Suspected causes are infectious-allergic bacterial (hemolytic streptococci), drug-allergic, or viral(zoster virus, HHV-7, Epstein-Barr virus; SARS-CoV-2 (Mäkilä T et al. 2022), adenoviruses - Costa-Silva M et al. 2017; Horie C et al. 2018).

Occurred in isolated cases after vaccinations (Merlotto MR et al. 2020; Gunatheesan S et al. 2012, Castro BA et al. 2015), including after COVID-19 mRNA vaccination (Palmén J et al. (2022).

Proximity to cutaneous T-cell lymphomas is discussed (evidence of a monoclonal rearrangement of the T-cell receptor in > 50% of cases!).

The concept of immune complex vasculitis is based on the detection of immunoglobulins and complement in the junctional zone of the skin as well as in walls of dermal vessels.

More frequent in the first two decades of life (6-18 years). Less frequent in infants.

Frequency peaks at 5 and 10 years;

Less frequently adults (middle age around 40 years) are affected.

Male sex preferred (m:w=3:1).

Trunk, flexor sides of extremities; oral mucosa and capillitium remain free (differentiation from varicella).

As with the "Heubner's star map" (see varicella below), there is a very polymorphic, only moderately itchy, possibly burning, but often (in 50% of patients) also completely asymptomatic exanthema. No mucosal infestation!

Acute onset with 0.2-0.4 cm erythema, red or reddish-brown lichenoid papules, initially with a smooth surface. These disintegrate rapidly, with lesional formation of erosions, ulcers and hemorrhagic crusts. Hemorrhagic vesicles are rarer. The recurrent and relapsing course of the disease leads to a coexistence of different efflorescences, with a correspondingly colorful (as in varicella) overall pattern.

Healing with the formation of varioliform scars.

Passenger hyperpigmentation or leukoderma. Itching is present in most patients; fever and arthralgia are rarer. About 30% of patients have no symptoms at all.

In rare cases, the disease can be highly febrile with severe general symptoms and sudden disseminated, crusty ulcerations. Particularly in adults, this complicative form of the disease can also be fatal (although this is extremely rare!).

The highly febrile ulceronecrotic form of PLEVA (pityriasis lichenoides with ulcers and hyperthermia = PLUH), which is associated with a severe feeling of illness, is regarded as an extremely rare variant of PLEVA (50 cases in the literature to date).

Occasionally, skin changes are also observed in patients with lymphomatoid papulosis, which are indistinguishable from pityriasis lichenoides acuta et varioliformis.

Not relevant. Inflammation parameters (CRP, BSG) slightly increased.

Lichenoid interface dermatitis with edema of the papillary body and exocytosis of lymphocytes and neutrophilic ganulocytes. The surface epithelium shows irregular acanthosis, a two-layered structure of the str. corneum with basket-weave-like orthokeratosis over a continuous parakeratosis zone.

Differently pronounced inter- and intracellular edema in the epidermis up to intraepidermal vesiculation; focal necrosis of the epidermis possible in the center of the lesion.

In the dermis, wedge-shaped, perivascular or interstitial infiltrate of CD8+ lymphocytes (occasionally also mixed with large lymphocytic irritant forms) and a few neutrophil granulocytes. T-cell clonality is often detectable. Leukocytoclastic vasculitis may develop if the clinical picture is pronounced, particularly in the case of ulceronecrotic progression.

Focal erythrocyte extravasations. Swelling of the endothelia, circumscribed erythrocyte diapedesis.

Immunohistology: Mostly _C3 and/or IgM in the vascular walls of the upper dermal plexus.

• Clinical Differentials:
  • Varicella: Clinical morphology may be very similar. Different pattern of involvement with involvement of oral mucosa and capillitium.
  • Köhlmeier-Degos disease: Rare, vasculitic systemic disease with diagnostic landmark clinic (disseminated papules with spatter-like atrophies in the center).
  • Drug ex anthem: No asynchronous polymorphism but rather monomorphic exanthem.
  • Syphilis: Syphilides are usually accompanied by LK swellings, the appearance rather monomorphic, frequently affecting palms and face. Serology is conclusive! Histology is conclusive (plasma cell-rich dermatitis).
  • Tuberculid, papulonecrotic: chronicity, evidence of active tuberculosis.
• Histologic differential diagnoses:
  • Acute and subacute eczema: spongiosis, planar parakeratosis, no keratinocyte necrosis, in atopic eczema possible eosinophilia.
  • Fixed drug reaction: apoptotic keratinocytes, vacuolated junctional zone, satellite necrosis, perivascular lymphocytic infiltrate.
  • Psoriasis guttata: acanthosis, hyper- and parakeratosis with neutrophil inclusions, no keratinocyte necrosis; diffuse, also perivascular condensed lymphocytic infiltrate with neutrophil granulocytes, no erythrocyte extravasations, vigorous epidermotropism.
  • Pityriasis rosea: edema of papillary body, focal spongiosis, no apoptotic keratinocytes, superficial perivascular lymphocytic infiltrate, few eosinophils.
  • Early syphilis: interface dermatitis with psoriasiform epidermal reaction dense, band-like infiltrate in upper and middle dermis (lymphocytes, histiocytes and plasma cells; also epithelioid cell component. Extension of the infiltrate to the deep vascular plexus.
  • Köhlmeier-Degos disease:superficial and deep perivascular lymphocytic infiltrate. Epithelial necrosis, with wedge-shaped connective tissue necrosis.

Good experience exists with erythromycin administration(3x500mg/day for 10 days), possibly in combination with glucocorticoids such as prednisolone (e.g. Decortin H initially 1mg/kgKG/day, rapid reduction).

For more severe pruritus, systemic antihistamine such as clemastine (e.g. Tavegil) 1-2 mg/day or desloratadine (e.g. Aerius) 5-10 mg/day p.o..

In the ulceronecrotic, febrile course, methotrexate (7.5-10.0 mg/m2 KO/week p.o. is recommended, possibly in combination with oral glucocorticoids(methylprednisolone 1-2 mg/kg bw/day).

Good response from TNF antagonists has been reported. IVIG (Marenco F et al. 2010) and extracorporeal photopheresis have also been used in individual cases.

Frequent healing after relapse or recurrent course in an average period of 18 months (4-108 months; Ersoy-Evans S et al. 2007).

Transition to pityriasis lichenoides chronica is possible.

Only in rare cases of the febrile, ulceronecrotic form of progression can life-threatening complications develop.

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2. Castro BA et al (2015) Pityriasis lichenoides et varioliformis acuta after influenza vaccine. An Bras Dermatol 90(3 Suppl 1):181-184.
3. de Unamuno Bustos B et al. (2014) Adult pityriasis lichenoides-like mycosis fungoides: a clinical variant of mycosis fungoides. Int J Dermatol 53:1331-1338.
4. Ersoy-Evans S et al (2007) Pityriasis lichenoides in childhood: a retrospective review of 124 patients. J Am Acad Dermatol 56:205-210.
5. Gardlo K et al (2003) PUVA -therapy of severe pityriasis lichenoides et varioliformis acuta. Dermatologist 54: 984-985
6. Gunatheesan S et al (2012) Pityriasis lichenoides et varioliformis acuta: a rare association with the measles, mumps and rubella vaccine. Australas J Dermatol 53:e76-78.
7. Habermann R (1925) On the acute necrotizing subtype of pityriasis lichenoides (pityriasis lichenoides et varioliformis acuta). Dermatol Z 45: 42-48
8. Horie C et al. (2018) Varicella zoster virus as a possible trigger for the development of pityriasis lichenoides et varioliformis acuta: retrospective analysis of our institutional cases. Clinical and experimental dermatology 43:703-707.
9. Mäkilä T et al. (2022) Pityriasis lichenoides et varioliformis acuta after SARS-CoV-2 infection and relapse after vaccination. J Eur Acad Dermatol Venereol 36:e431-e433.
10. Marenco F et al (2010) High-dose immunoglobulins and extracorporeal photochemotherapy in the treatment of febrile ulceronecrotic Mucha-Habermann disease. Dermatol Ther 23:419-422.
11. Martinez-Escala ME et al (2014) γδ T cell-rich variants of pityriasis lichenoides and lymphomatoid papulosis: benign cutaneous disorders to be distinguished from aggressive cutaneous γδ T cell lymphomas. Br J Dermatol doi: 10.1111/bjd.13364.
12. Merlotto MR et al (2020) Pityriasis lichenoides et varioliformis acuta following anti-tetanus and diphtheria adult vaccine. An Bras Dermatol 95:259-260.
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14. Mucha V (1916) On a peculiar case close to parakeratosis variegata (Unna) or pityriasis lichenoides chronica (Neisser-Juliusberg). Arch Dermatol Syph 123: 586-592
15. Nofal A et al (2016) Febrile ulceronecrotic Mucha-Habermann disease: proposed diagnostic criteria and therapeutic evaluation. Int J Dermatol 55:729-738.
16. Palmén J et al (2022) Pityriasis lichenoides et varioliformis acuta following COVID-19 mRNA vaccination. J Eur Acad Dermatol Venereol 36:e327-e328.
17. Weinberg JM et al (2002) The clonal nature ot pityriasis lichonides. Arch Dermatol 138: 1063-1067.