Generalized red patches

Introduction It is a red plaque that is caused by various factors. It can be seen in seborrheic dermatitis, which occurs in areas with more sebaceous glands, such as the head, face, back of the ear, armpits, chest, scapula, groin, perineum, etc. The initial rash is red papules or patches that fuse with each other and are covered with greasy scales or jaundice.

Cause

Common in seborrheic dermatitis.

The cause of seborrheic dermatitis:

1, the diet is too fat and greasy [1], sugar, excessive fat, drinking, overeating spicy and greasy food, endocrine dysfunction, digestive dysfunction.

2, hemorrhoids. Seborrheic dermatitis can be caused by adolescent acne vulgaris or adult acne (toxic acne) that is not cured in time or improperly treated.

3, improper care, abuse of skin care products hurt the skin's own water and oil balance function, skin water and oil metabolism disorders. The pH of healthy skin surfaces is about 5.2-5.5, which is not conducive to bacterial growth. Because chemical substances (cosmetics, skin care products), increased sebum secretion, and changes in chemical composition, the inhibition of bacterial effects is reduced, and normal bacteria such as staphylococcus, malaria pityriasis, and streptococci present on the surface of the skin are caused. , mass reproduction, invading the skin and causing disease.

4, metabolic disorders, genetic factors, vitamin B deficiency and physical, chemical stimulation, it is often scratched or with alkaline detergents can aggravate the onset of seborrheic dermatitis.

5, nervous, overworked, bacterial infection. On the basis of excessive seborrhea, seborrheic dermatitis can be secondary to fungi (P. ovale) and bacteria (Acne propioni) infection, and it can also cause acne symptoms; it can also be secondary to allergic reactions to fungi and bacteria. The self-immune response may also be followed by the occurrence of eczema-like lesions and disseminated seborrheic dermatitis.

6, related to gonad secretion disorder, caused by hyperandrogen secretion. In addition, some believe that it may be related to immune, genetic, hormonal, neurological and environmental factors.

7, allergies, allergic skin. Many seborrheic dermatitis are allergic to it.

an examination

Related inspection

Skin smear microscopy skin color

Clinical manifestation

1. Typical skin lesions are dark yellow-red spots, patches or maculopapular rash with clear edges, and the surface is covered with greasy scales or suede. The clinical manifestations are slightly different due to the different sites of lesions.

2. The rash occurs in the scalp, eyebrows, eyelids, nose and sides, behind the ear, neck, chest and upper back scapula, axillary fossa, groin, umbilical fossa and other areas with rich distribution of sebaceous glands.

3. Conscious symptoms are varying degrees of itching.

4. Infant seborrheic dermatitis often occurs in the first month after birth. The skin lesions are mostly in the scalp, forehead, eyebrows and cheeks. It is a spilled red patch with jaundice.

5. Adults generally have seborrheic dermatitis: oily is also dry or mixed, itching. Symptoms such as desquamation on the surface of the skin, erythema is more obvious.

Diagnose based on

Seborrheic dermatitis, also known as seborrheic alopecia, often occurs after seborrheic dermatitis, usually starting from the top of the head. The initial symptom of dermatitis is inflammation of the skin centered on the hair follicle, which is characterized by small papules, which gradually enlarge and form a damp oily scaly plaque with clear boundaries. In severe cases, the scalp can be covered with filthy mink. . There is also a relatively dry, gray-white scaly scale-dandruff on the head. The former is called wet seborrheic dermatitis, and the latter is called dry seborrheic dermatitis. Both are itchy and can cause hair to fall off. The pathogen causing dermatitis is a fungus.

Fungal seborrheic dermatitis, first of all, sebum secretion is too much, the fungus takes advantage of the virtual, causing chronic inflammation of the skin, which in turn causes a series of inflammatory reactions of the sac, causing hair growth, development, metabolic disorders, and the hair will be sparsely pulled. The ground has fallen off.

It is very different from the baldness of the symptoms of hair loss without sebum secretion.

Excessive sebum secretion is associated with nervous system or endocrine dysfunction. Constipation and eating stimulating food may be the predisposing factors. It is also one of the reasons for eating too much fat and shampooing too frequently. In the past, there were very few people with seborrheic dermatitis, which were related to their vegetarianism and nervous system. Frequent shampooing, destroying the obstruction of the sebaceous glands, causing excessive secretion of sebum, forming a hotbed of fungi with fatty acids.

Differential diagnosis

Identification of seborrheic dermatitis and similar diseases:

1. Psoriasis of the head and face: The damage is dispersed into flakes, the boundary is clear, the scales are thick, the touch is uneven, the hair does not fall off, the short hair gathers into a bundle, and the heavy damage can be connected into a large piece, extending to the front hairline Invaded the forehead a few centimeters. Scratch the scales with a film phenomenon (ie, the scales are scraped off, under which is a red shiny film) and bleeding phenomenon (ie, the light scratch film can appear scattered at small bleeding points), film phenomenon and bleeding phenomenon is important for psoriasis damage feature.

2. Rose pityriasis: It occurs in the neck, torso, and proximal extremities. It is an oval-shaped rash with a yellowish center and a slightly elevated edge. It is light red with white squama-like scales. From the beginning, it is a single lesion, called the mother spot; the mother spot is gradually larger, the diameter can reach 2~5cm or more, sometimes there are 2~3 mother spots at the same time, and after 1~2 months, small erythema appears successively. Occurred in the trunk, the long axis of the rash is consistent with the skin pattern, usually 4 to 6 weeks can self-resolve, no recurrence.

3. Body: damage the edge of the ridge and narrow. The realm is clear, and there is a ring-shaped damage that the central healing expands to the surroundings. Itching is obvious, patients often have a history of hand and foot hyperthyroidism.

4. erythematous pemphigus: mainly distributed in the face, neck, chest and back in the middle. Beginning on the face with symmetrical erythema, overlying scales and scarring, blister on the back of the neck and chest and back erythema, the formation of suede after rupture, Nie's sign positive. (ie, applying pressure on the blister top, you can see the blister infiltration into the surrounding epidermis; pulling the residual wall of the blister wall, causing further exfoliation of the surrounding epidermis; more importantly, the skin with normal appearance is also rubbed and broken).

5. Alcoholic dermatitis: does not involve the scalp. Eyebrows and nasolabial folds are not good sites, and there are many medications for long-term external application of hormone preparations.

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