Pityriasis lichenoides (et varioliformis) acuta L41.0

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

Many authors consider pityriasis lichenoides et varioliformis acuta to be an acute form of pityriasis lichenoides, so that 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.

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; 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).

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).

Torso, flexed sides of the extremities. Oral mucosa and capillitium remained free (differentiation from varicella).

As with the "Heubner's star map" (see below varicella) very polymorphic, only moderately itchy, possibly burning, but frequently (in 50% of the patients) also asymptomatic exanthema.

Acute onset with 0.2-0.4 cm large erythema, red or reddish-brown initially surface-smooth lichenoid papules. 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 colourful (as in varicella) overall pattern.

Healing with formation of varioliform scars.

Passenger hyperpigmentation or leukoderm. Most patients experience itching; fever and arthralgia are less frequent. About 30% of patients have no symptoms at all.

In rare cases, the disease can be highly febrile with severe general symptoms and suddenly occurring disseminated, crusty ulcers. Particularly in adulthood, this complicated form of the disease can also end fatally (although this is extremely rare!).

As an extremely rare variant of PLEVA (50 cases in the literature so far) the highly febrile ulceronecrotic course (pityriasis lichenoides with ulcers and hyperthermia = PLUH) is considered, which is accompanied by severe feeling of illness.

Occasionally, skin changes are also observed in patients with lymphomatoid papulosis, which cannot be distinguished from pityriasis lichenoides acuta et varioliformis.

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

Interface dermatitis with irregular acanthosis, two-layer structure of the stratum corneum with plexus-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.

In the dermis wedge-shaped, perivascular or interstitial infiltrate of CD8+ lymphocytes (occasionally mixed with large lymphocytic irritants) and a few neutrophilic granulocytes. A T-cell clonality is often detectable.

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

Immunohistology: Mostly_C3 and/or IgM in the vessel walls of the upper dermal plexus.

• Clinical differential diagnosis:
• Varicella: Clinical morphology can be very similar. Different pattern of infection with involvement of the oral mucosa and capillitium.
• Drug exanthema: No asynchronous polymorphism but rather monomorphic exanthema.
• Syphilis: Syphilis is usually accompanied by swelling of the lungs, the appearance is more monomorphic, often affecting the palms and face. Serology is proving! Histology is pioneering (plasmacellular dermatitis).
• Tuberculide, papulonecrotic: chronicity, evidence of active tuberculosis.
• Histological differential diagnoses:
• Acute and subacute eczema: spongiosis, extensive parakeratosis, no keratinocyte necrosis, possible eosinophilia in atopic eczema.
• Fixed drug reaction: apoptotic keratinocytes, vacuolated junctional zone, satellite necrosis, perivascular lymphocytic infiltrate.
• Guttate psoriasis: acanthosis, hyper- and parakeratosis with neutrophil inclusions, no keratinocyte necroses; diffuse, also perivascularly compressed lymphocytic infiltrate with neutrophil granulocytes, no erythrocyte extravasations, strong epidermotropism.
• Pityriasis rosea: edema of the papillary body, focal spongiosis, no apoptotic keratinocytes, superficial perivascular lymphocyte infiltrate, few eosinophils.
• Early syphilis: interface dermatitis with psoriasiform epidermal reaction dense, band-shaped infiltrate in the upper and middle dermis (lymphocytes, histiocytes and plasma cells; also epitheloid cell component. Extension of the infiltrate to the deep vascular plexus.

Good experience has been made with erythromycin administration (3x500mg/day for 10 days), possibly in combination with glucocorticoids such as prednisolone (e.g. Decortin H initial 1mg/kgkgKG/day, rapid reduction).

In case of severe itching systemic antihistamine such as Clemastin (e.g. Tavegil) 1-2 mg/day or Desloratadine (e.g. Aerius) 5-10 mg/day p.o.

In the ulceronecrotic, febrile form of the disease, 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).

Frequent healing after a relapse or recurrent course over 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 febrile ulceronecrotic progression can life-threatening complications arise.

1. Costa-Silva M et al. (2017) Pityriasis lichenoides et varioliformis acuta associated with human herpesvirus.
2. 7th Actas Dermosifiliogr. doi: 10.1016/j.ad.2017.03.023.
3. Castro BA et al (2015) Pityriasis lichenoides et varioliformis acuta after influenza vaccine. An Bras Dermatol 90(3 Suppl 1):181-184.
4. 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
5. Ersoy-Evans S et al (2007) Pityriasis lichenoides in childhood: a retrospective review of 124 patients. J Am Acad Dermatol 56:205-210
6. Gardlo K et al (2003) PUVA therapy of severe pityriasis lichenoides et varioliformis acuta. Dermatologist 54: 984-985
7. 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.
8. Habermann R (1925) On the acute necrotizing subtype of pityriasis lichenoides (pityriasis lichenoides et varioliformis acuta). Dermatol Z 45: 42-48
9. 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.
10. 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.
11. Merlotto MR et al (2020) Pityriasis lichenoides et varioliformis acuta following anti-tetanus and diphtheria adult vaccine. An Bras Dermatol 95:259-260.
12. Miyamoto T et al (2003) Febrile ulceronecrotic Mucha-Habermann disease: a case report and a review of the literature. J Clin Pathol 56: 795-797
13. Mucha V (1916) On a peculiar case close to parakeratosis variegata (Unna) or pityriasis lichenoides chronica (Neisser-Juliusberg). Arch Dermatol Syph 123: 586-592
14. Weinberg JM et al (2002) The clonal nature ot pityriasis lichonides. Arch Dermatol 138: 1063-1067