Parapsoriasis Types

There seem to be 4 main types of parapsoriasis:

1. Pityriasis lichenoides et varioliformis acuta (PLEVA; aka Mucha Habermann's Disease);
2. Pityriasis lichenoides chronica (PLC);
3. Plaque parapsoriasis small/large (parapsoriasis en plaque; SPP/LPP);
4. Lymphomatoid papulosis (LyP).

1. Pityriasis lichenoides et varioliformis acuta (PLEVA)

PLEVA parapsoriasis is believed to be a disease of immune system (not necessarily genetic). Its symptoms are small (around 5 mm in diameter) raspberry-red rashes on the skin. A fresh rash is can be accompanied by burning and pain.

Pink plaques may have papules with red-brown crusts in their centers.

PLEVA is most commonly developed in young boys.

PLEVA more frequently appears on the hands, feet, scalp, and sometimes also the face.

PLEVA parapsoriasis is often misdiagnosed as chickenpox or rosacea, but also may be misdiagnosed as a guttate psoriasis.

PLEVA parapsoriasis may be triggered by infectious and bacterial diseases (i.e. strep throat, sinusitis, tonsillitis, caries, cholecystitis, etc.) and vaccinations, which is also similar to guttate psoriasis. However, the exact causes of PLEVA para psoriasis are unknown.

With PLEVA parapsoriasis, the T cells (immune system cells) start to cause skin lesions. Psoriasis also has overactive T cells.

Similar to psoriasis, PLEVA parapsoriasis can be treated by UVB and topical steroids, but unlike psoriasis - also by antibiotics.

Pityriasis lichenoides et varioliformis acuta (PLEVA) is a more severe version of Pityriasis lichenoides chronica (PLC).

2. Pityriasis lichenoides chronica (PLC)

PLC parapsoriasis is a chronic version of a PLEVA parapsoriasis. However, PLC is usually less severe than PLEVA.

3. Plaque Parapsoriasis (parapsoriasis en plaque)

There's yet another parapsoriasis, the so-called Plaque Parapsoriasis (parapsoriasis en plaque):

• Small plaque parapsoriasis (SPP);
• Large plaque parapsoriasis (LPP).

Small plaque parapsoriasis (SPP)

Small plaque parapsoriasis is a benign disorder.

Small plaque parapsoriasis is characterized by spots and plaques with a diameter up to 5 cm, of a rounded, oval, or irregular shape. The color of the plaques can vary from red to cyan to yellow to light brown. The plaques have clear boundaries with thin transparent scales on the surface. Lesions can be located in the region of the stomach and chest, with no itch.

Small plaque parapsoriasis lasts several months to years and can disappear on its own.

Large plaque parapsoriasis (LPP)

Large plaque parapsoriasis has oval, hardly delimited from healthy skin, plaques with a diameter of about 5-10 cm.

The color of the plaques varies from red to blue to light brown. The lesions have thin scales on their surface. Lesions are arranged symmetrically on the body, thighs, buttocks, and chest. Itch is absent or insignificant. Skin atrophy can precede the development of lymphoma.

Large plaque parapsoriasis is chronic with spontaneous remissions and flare-ups.

In about 10% of the patients large plaque parapsoriasis may progress to CTCL - Cutaneous T-cell Lymphoma.

Cutaneous T-cell lymphomais a type of immune system cancer. CTCL is caused by a mutation of helper T cells. Clusters of malignant T cells are pushed to the epidermis, as the body is trying to get rid of them. This causes skin lesions and plaques, which eventually start forming cancer tumors. The tumors may then spread to lymphnodes and other internal body organs.

Some think that large plaque parapsoriasis is actually the earliest stage of the Cutaneous T-cell Lymphoma, the patch stage.

Large plaque parapsoriasis has a high risk of regeneration into a malignant skin lymphoma; therefore, it requires continuous observation and treatment in order to prevent its progression into CTCL.

4. Lymphomatoid papulosis (LyP)

LyP is an extremely rare parapsoriasis affecting 0.0001% - 0.0002% of the population.

LyP is a histologically malignant but clinically benign disorder.

LyP shows as recurrent multiple pruritic papules, predominantly on the trunk and limbs.

The papules heal on their own after about 1-2 months, usually leaving slightly lowered oval scars.