What Is Pityriasis Rosea?

Pityriasis rosea is a common inflammatory skin disease that occurs frequently in the trunk and the extremities, with varying numbers of rose patches with sugary scales on them. The disease is self-limiting and usually lasts 6 to 8 weeks And self-healing. However, there are also cases of unhealed, because many patients with pityriasis rosea are easily left with pigmentation after delaying treatment. Should be treated early.

Basic Information

English name: pityriasis rosea
Visiting department: dermatology
Multiple groups: Young or middle-aged

Common locations: Proximal torso and limbs
Common causes: Viral infection related
Common symptoms: Uncertain number of rose patches

Causes of pityriasis rosea

Not clear yet. Because the disease has a seasonal onset, the rash is self-limiting, and rarely recurs. It is a precursor spot at first, and no definite allergic substance has been found to cause the disease. Therefore, most of them are thought to be related to viral infection. The results suggest that the incidence of roseola is directly related to Coxsackie B virus infection. In addition, the cause of fungi, bacterial infections, or other microorganisms such as Borrelia has not been proven. It is also thought to be an allergic reaction to a certain infection or a manifestation of gastrointestinal poisoning.

Clinical manifestations of pityriasis rosea

The disease is more common in young or middle-aged people, with frequent occurrence in spring and autumn. The initial damage is the appearance of rose-red spots with a diameter of 1 to 3 cm on the trunk or limbs, with thin scales, called precursor spots, and the number is 1 to 3. After 1 to 2 weeks, red patches of varying sizes appear on the trunk and limbs, often symmetrically distributed. It starts on the trunk and gradually develops into the limbs. Patches vary in size, ranging from 0.2 to 1 cm in diameter, and are often oval in shape. There are fine scales in the middle of the patch, and a thin layer of free scales inward on the edge of the circle. The long axis of the patch and ribs or The skin is parallel. May be accompanied by varying degrees of itching. In a few patients, skin lesions are limited to the head and neck or limbs.

A small number of patients start with red pimples, which can fuse into patches. These patients often have itching, known as pimples type pityriasis.

In another group of patients, the onset is rapid and there are no precursor spots. Most of them have large red patches or maculopapular rashes in the lower abdomen or the inner thigh. The peeling off of the scalp skin showed roserose-like skin lesions. Such patients may be caused by self-sensitivity reactions, so it is called rose-type autosensitivity dermatitis.

Pityriasis rosea test

Histopathology: changes in non-specific chronic inflammation, focal keratosis in the epidermis, mild thickening of the spinous layer, sponge formation and intracellular edema, moderate vascular dilatation in the superficial dermis, edema and lymphocyte infiltration.

Diagnosis of pityriasis rosea

According to the precursor spots, the appearance of the rash has a typical red circle-like brachial scaly patch with the free edge inward, and the long axis of the rash is parallel to the skin line, which is not difficult to diagnose.

Differential diagnosis of pityriasis rosea

Identification of the following diseases:

Psoriasis

The rash occurs frequently on the extremities of the extremities and on the knees. There are silvery white scales. Auspitz's sign can be seen when the scales are scraped. Early rashes worsen in winter, and subside or decrease in summer.

2. Seborrheic Dermatitis

The rash occurs on the head, face, and chest. Oily scales can be seen on the rash on the hair, and hair loss can occur. There is no special arrangement of the rash on the trunk and no precursor spots.

3. Tinea versicolor

There was no particular rash arrangement on the trunk, and fungal microscopy was positive.

4. Syphilis

Macular syphilis lesions are of the same size and quickly turn pale brown, without scales or only a few scales, with systemic lymphadenopathy, and seropositivity.

Pityriasis rosea treatment

Because the disease is self-limiting, the purpose of treatment is to reduce symptoms and shorten the course of the disease.

General treatment

In the acute phase, hot water washing and soap washing are contraindicated. Ban irritating topical drugs. Clinically, many patients have been exacerbated due to improper local care, prolonged the course of the disease, or turned into auto-sensitive dermatitis.

2. Antihistamines

Antihistamines such as chlorpheniramine, cyproheptadine, terfenadine and keminone can be used as appropriate. Vitamin C is also available.

3. Traditional Chinese Medicine

The principle of treatment of Chinese medicine is to clear heat and cool blood, expel wind and relieve itch, and generally use Liangxue Xiaofeng Decoction is effective. For light patients, it is effective to use purple grass and decoction, once a day.

4. Ultraviolet radiation

After the period of acute inflammation has passed, the use of ultraviolet spot radiation can promote the regression of damage.

5. Topical treatment

Calamine lotion can be applied externally.