Parapsoriasis

Introduction to parapsoriasis Parapsoriasis is a relatively rare group of skin diseases. No obvious symptoms, long duration, no satisfactory treatment. In the case of an acute mossy pityriasis, it is a generalized red or brown scaly flat papule, often with necrosis, blisters and bleeding. The rash occurs in batches, and lesions at different stages of development are often found at the same time. basic knowledge The proportion of the disease: both parents are psoriasis patients, the incidence rate of children is 50% to 66% Susceptible people: no special people Mode of infection: non-infectious Complications: psoriasis

Cause of parapsoriasis

Cause of the disease (40%):

The etiology is still unclear. The common feature of histopathology is the abnormal proliferative disease of dermal T cells. Therefore, this group of diseases is considered to have a certain correlation with mycosis fungoides.

Pathogenesis (25%):

Southern blotting and PCR analysis of T cell receptor gene rearrangement showed the presence of dominant T cell clonal populations, suggesting that the abnormal regulation of local infiltrating cells is related to the occurrence and progression of this disease.

Parapsoriasis prevention

Prevention: remove possible causes, strengthen nutrition, improve immunity, and diagnose early treatment. Treat the disease correctly and maintain a good attitude.

Parapsoriasis complications Complications psoriasis

Mossy-like parapsoriasis, such as itching, is often a sign of a shift to a mycosis fungoides.

Parapsysis Symptoms Common symptoms Granuloma dysplasia pustular lymph nodes swollen maculopapular punctate bleeding acne scars

The diagnostic terminology and classification of this group of diseases have been confusing. The current classifications are: parapsoriasis guttata, parapsoriasis Varioliformis, mossy rash Disease (parapsoriasis lichenoides), small plaque parapsoriasis, large plaque parapsoriasis, each type has different skin lesions and morphological changes, some scholars Lymphoma-like papulosis is considered to be a heterotypic form of lichen-type parapsoriasis, but it is also considered to be a group of independent diseases.

Parapsoriasis guttata, also known as chronic lichen-like pityriasis, is more common.

Mossy-like parapsoriasis lichenoides, a rare form of this type, may evolve into mycosis fungoides.

Small plaque parapsoriasis, also known as digitate dermotosis.

Large plaque parapsoriasis, which is rare, has the potential to evolve into mycosis fungoides.

Parapsoriasis varioliformis, also known as acute acne-like lichen-like pityriasis, is a rare form of this type, which is classified as a vasculitis.

1. Drip-type parapsoriasis: more common in children and young people, about 2/3 of men, no obvious symptoms, skin lesions are mostly reddish or reddish brown needles to the size of the invasive rash or maculopapular rash. The surface is covered with fine scales, and the surface is smooth after peeling. There is no bleeding point. The skin lesions do not fuse with each other. They are scattered in the trunk, limbs, etc., and the head, palmar and mucous membranes are rare. After about 3 to 4 weeks, the lesions are damaged. Gradually flattened and subsided, leaving temporary hypopigmentation spots, but there may still be new rashes, so new and old skin lesions can be seen at the same time, the course of the disease is slow, usually about half a year can gradually fade, but also for several years, but health Not affected.

2. Mossy-like parapsoriasis: skin lesions are some similar to lichen planus miliary to rice large flat small papules, the color is fresh red, the gradient is yellow red, deep red or purple, the surface is covered with fine gray-white scales, gathered into Reticular plaque, after the skin lesions gradually shrink, telangiectasia and punctate pigmentation, similar to the lesions of vascular atrophic skin heterochromia, occur on both sides of the neck, trunk, limbs and breasts, pole Rarely seen in the face, palmar and mucous membranes, can occur in the hands and feet can be sputum, after very slow can remain unchanged for many years, the symptoms are not, but if itching, often a sign of the transformation to sputum granuloma, should pay attention Once it develops into a mycosis granuloma, the itching is reduced or disappeared.

3. Large plaque-type parapsoriasis: occurs in middle-aged and elderly men, with mild symptoms, skin lesions with clear plaques, coins to palms, variable numbers, mild infiltration, and early red or yellow color Red, the gradient is dark red or dark purple red, the surface is covered with a small amount of scales, not easy to peel off, no point bleeding, the skin lesions can be leopard-like appearance or arrangement consistent with the ribs, good for the trunk, proximal limbs, head, Hand and foot can be involved, does not invade the mucosa, the course of the disease is slow, generally does not naturally subside. After a long illness, there is a mossy hypertrophy or atrophy, similar to the appearance of cutaneous heterochromia, Ackerman believes that this is the patch-stage damage of mycosis fungoides.

4. Small plaque-type parapsoriasis: skin lesions are pink to yellow-red, oval or elongated in scattered patches or thin plaques, often finger-printed patches, covered with a few scales, 1 to 5 cm in diameter Symmetrical distribution in the trunk and proximal extremities, no obvious symptoms, the general health of patients is not affected.

5. Acne-like parapsoriasis: more common in adolescents, infants and the elderly are rare, acute onset, skin lesions are pale red or reddish brown needles to lentils, large edematous erythema, round papules, herpes, or pustules, Can cause varicella-like vesicles, severe cases of blister bleeding, necrosis, scarring, and even the formation of necrotizing ulcers, leaving a slight pigmentation or hypopigmentation after regression, can also leave a slight atrophy, more suddenly appear in the trunk, Axillary fossa, limbs flexed, not involved in palmar, mucous membranes, can be generalized in severe cases, rashes about 2 weeks to cure, but new rash can occur one after another, so the course can last for months, even years, general health is not Effects can be accompanied by fever, fatigue, joint pain and swollen lymph nodes.

Examination of parapsoriasis

Histopathological examinations have different manifestations in each type. In acute lichen-like pityriasis, the epidermis is extensively parakeratized, focal epidermal degeneration or necrosis; dermal mononuclear cells infiltrate and invade the epidermis, small blood vessels dilate, congestion, and hemorrhage. Atypical lymphocytes are sometimes seen. The tissue of chronic lichen-like pityriasis is basically the same as that of the acute type, but there is no epidermal necrosis and atypical lymphocytes. The early lesions of small plaques and large plaque-like parapsoriasis are non-specific and are generally chronic inflammation. However, in the late stage of large plaque parapsoriasis, many atypical lymphocytes (ie, mycosis fungoides) are seen in the dermis and epidermis. For suspicious cases, DNA rearrangement of the T cell receptor gene can be sent.

Diagnosis and identification of parapsoriasis

Diagnostic criteria

1. Drip-type psoriasis

(1) More common in children and young people, about 2/3 are male, no obvious symptoms.

(2) Skin lesions are invasive macules or maculopapular rashes with most reddish or reddish brown needles to the size of the fingernails. The surface is covered with fine scales. After peeling, the hair is smooth and there is no bleeding. The skin lesions do not fuse with each other. Distributed in the trunk, limbs, etc., the head, palmar and mucous membranes are rare.

(3) After about 3 to 4 weeks, the skin lesions gradually flatten and disappear, leaving temporary pigmentation spots, but new rashes can still appear, so new and old skin lesions can be seen at the same time.

(4) The course of the disease is slow. It usually fades in about half a year. It also has several years of unhealed, but health is not affected.

2. Mossy-like parapsoriasis

(1) Skin lesions are some flat lichen-like miliary to rice large flat small papules, the color is fresh red, the gradient is yellow red, deep red or purple, the surface is covered with thin gray-white scales, gathered into a network of patches, later Skin lesions gradually shrink, with telangiectasia and punctate pigmentation, similar to lesions in vascular atrophic skin heterochromia.

(2) Occurs on both sides of the neck, trunk, limbs and breasts, rarely seen in the face, palmar and mucous membranes, which can occur in the hands and feet.

(3) After being extremely slow, it can remain as it is for many years, and the symptoms are not felt, but if itching, it is often a sign of a transition to a sputum granuloma. It should be noted that once it develops into a mycosis granuloma, the itching is reduced or disappeared. .

3. Large plaque-type parapsoriasis

(1) Occurs in middle-aged and elderly men, and the symptoms are mild.

(2) Skin lesions are clear plaques, coins to palms are large, the number is variable, there is mild infiltration, the color is bright red or yellow red at first, the gradient is dark red or dark purple, the surface is covered with a small amount of scales, not easy to peel off No punctiform hemorrhage, the skin lesions may have a leopard skin appearance or arrangement consistent with the ribs.

(3) It is good to the trunk, the proximal limbs, the head, the hands and feet can be involved, and does not invade the mucosa.

(4) The course of the disease is slow, and generally does not naturally subside. After a long illness, there is a mossy hypertrophy or atrophy, similar to the appearance of heterochromia, which Ackerman believes is the patch damage of mycosis fungoides.

4. Small plaque-type parapsoriasis

(1) The skin lesions are pink to yellowish red, oval or elongated in scattered patches or thin plaques, often referred to as patch-like patches, covered with a small scale, 1 to 5 cm in diameter.

(2) Symmetrical distribution in the trunk and proximal extremities, no obvious symptoms, the general health of patients is not affected.

5. Acne-like parapsoriasis

(1) More common in adolescents, infants and the elderly are rare.

(2) acute onset, skin lesions are reddish or reddish brown needles to lentils large edematous erythema, round papules, herpes or pustules, some may cause varicella-like blisters, severe cases of blister bleeding, necrosis, knot Hey, even a necrotizing ulcer.

(3) After remission, mild pigmentation or hypopigmentation may remain, and mild atrophy may remain.

(4) Suddenly appear in the trunk, armpits, limbs flexed, not involved in palmar, mucous membranes, can be generalized in severe cases, the rash is about 2 weeks to cure, but new rash can occur one after another, so the disease can last for several months Even for years.

(5) General health is not affected, may be accompanied by fever, fatigue, joint pain and lymphadenopathy.

Differential diagnosis

1. Differential diagnosis of drip type psoriasis

(1) Drip-like psoriasis: scaly thick, mica-like, ablated basal hemorrhage, acute onset, often accompanied by angina or tonsillitis.

(2) pityriasis rosea: occurs in the trunk and the proximal extremities of the limbs. The long axis of the rash is consistent with the direction of the dermatoglyph. It has varying degrees of itching, short course of disease, and is not easy to relapse. Histopathology is difficult to distinguish. In general, pityriasis rosea Superficial inflammatory cell infiltration is more obvious, papilledema, often seen extravascular red blood cells.

2. Differential diagnosis of lichen-like parapsoriasis

(1) Lichen planus: The lesion is a purple-red polygonal flat papule with few scales and is not easily removed. There are Wickham lines, severe itching, and specific histopathological changes.

(2) vascular atrophic cutaneous heterochromia: occurs in the neck and chest and limbs, for localized damage, heterochromia, no papular lesions, slight or lack of epidermal scaly, conscious itch, histopathological keratosis, The dermal cells are infiltrated lightly, and the epidermis is atrophied, and does not evolve into mycosis fungoides.

(3) Invasive period of mycosis fungoides: early identification is not easy, but mycosis fungoides are often large plaque lesions, infiltration, consciously itchy, may be associated with fatigue, weight loss and visceral damage, histopathological specific Sexual changes can be seen in mycosis fungoides.

3. Differential diagnosis of large plaque-type parapsoriasis

(1) Seborrheic dermatitis: occurs in the fatty area, with fatty scales on the surface, a small number, light infiltration, and good treatment response.

(2) Invasive period of mycosis fungoides: The main identification is mainly histopathological changes.

4. Differential diagnosis of acne-like parapsoriasis

(1) Chickenpox: It is a viral infectious disease. According to the age of varicella, the clinical manifestations can be identified.

(2) Lymphoma-like papulosis: Amorphous cells can be seen in histopathology.

(3) papular necrotizing tuberculosis rash: often accompanied by tuberculosis in the lungs or other organs, histopathology has tuberculosis structure, and there is a cheese-like change.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.