Nodular lesions are larger and deeper than macules and papules, mostly invading deeper down into the dermis and reaching the subcutaneous tissue in severe cases. The surface is semicircular and smooth. The surface of inflammatory nodules is red, painful and angular, with a diameter of 0.5 to 5 cm. late nodules often break down, such as late syphilis nodular lesions, skin tuberculosis nodules are ulcerated and scarred. The nodules have deeper histopathological changes mostly in the deep dermis and can invade the subcutaneous fat layer, so they can be accompanied by lipid membrane and vascular type changes. The emetic has a slight pathological change in the superficial dermis, which differs from the spotted rash and papule pathological changes in the epidermis and superficial dermis. Depending on the etiology, nodules can be limited, asymmetric, and few in number; they can also be systemic, symmetric, and few or sparse in number. Nodular dermatoses generally have mild acute systemic symptoms, slow onset and relatively long course, such as cutaneous tuberculosis, syphilis, and chronic erythema nodosum migrans. Therefore, they are clinically different from maculopapular and papular skin diseases. Nodules are divided into two types: inflammatory and non-inflammatory.
I. Non-inflammatory nodules
1.Rheumatoid nodules
For autoimmune diseases
2.Late syphilis proximal joint nodules
For hard and tough end fibrotic nodules, no red tumor.
3.Skin pig cysticercosis nodules
Human ingestion of tapeworm eggs through the stomach and ten fat intestine hatching out of six hook larvae, cattle into the intestinal wall through the blood, lymphatic fluid into the subcutaneous formation of peanut rice large, round nodules.
4.Gout nodules
Gout is a source of gin metabolic disorders. Elevated serum uric acid, uric acid in the form of crystals deposited in the tissue to form gout nodules onset. Preferably in the toe joint.
5.Nodular xanthoma
It is a disorder of lipid metabolism, caused by high p-lipoproteinemia. The dermis has diffuse foam cell infiltration.
6.Nodular calcium deposits
Mostly seen in patients with childhood dermatomyositis, mostly in the onset of bony joint prominence.
7. Cutaneous pulmonary schistosome nodules
Often infected with pulmonary schistosomiasis.
8.Chronic nodular chondrodermatitis of the ear whorl
Mostly induced by traumatic frostbite.
9.Dermal black fever
The disease develops when Leishmania microsomes invade the skin. It can be primary or secondary to visceral infection.
Two, inflammatory nodules
1.Leprosy tuberculosis
The pathogenic bacteria are Mycobacterium leprae, acid-resistant stain positive, gram stain positive. The highest rate of the nasal whorl of tuberculosis and boundary type leprosy with bacteria. 200 million bacteria are excreted daily. Therefore, the respiratory tract is the main route of infection.
2.Skin tuberculosis
The pathogenic bacteria is Mycobacterium tuberculosis, acid-resistant stain positive, skin tuberculosis is reinfection, common for common lupus. Most of the infections are transmitted by skin trauma.
3. Sclerosing erythema
It is often caused by pulmonary tuberculosis or lymph node tuberculosis lesions, and is of the tuberculosis rash type.
4.Tuberculous nodular phlebitis
It often invades the lower leg and the edge of the foot and appears as erythematous nodules consistent with veins in strips.
5.Nasal sclerosing node disease
Caused by nasal sclerotia Klebsiella infection. For gram-negative short bacillus caused by the initial rhinitis, followed by nasopharynx, soft crotch, nose and the formation of hard tough purplish nodules.
6.Swimming pool granuloma
Infected by Mycobacterium pool, mostly infected by abrasions, easily occurring in elbows, knees, hands and feet and lower legs, producing brown nodules or plaques.
7, mycobacterial ulcer
The causative agent is Mycobacterium ulcerans, a saprophytic bacterium in tropical soil, which occurs in the lower legs and forearms, and is a painless solid nodule that can ulcerate and scar.
8, late nodular skin syphilis rash
The damage is composed of nodules arranged in a circular pattern, often breaking down.
9.Late stage cutaneous syphilis rubber swelling
Prevalent in the joint surface vulnerable to trauma and soft crotch, the size of about fingertip to walnut, hard and tough, asymptomatic, but easy to break down to form kidney-shaped and horseshoe-shaped.
10. Facial lupus cornea
Previously, it was thought to be a tuberculosis rash. Although there are tuberculosis-like changes on the histology, it is negative for tuberculin and has no tuberculosis lesions, so it is not considered to be related to tuberculosis.
11.Granuloma inguinalis
The pathogenic bacterium is a granulomatous Klebsiella gram-negative short bacillus with ovoid vesicles in mononuclear cells, i.e. Donovanbodies. hard nodules occur mostly in the perineum, genitalia, and perianal area, and the ruptured edges are elevated in papilloma-like hyperplasia. Properties of disseminated disease.
12, Acute febrile neutrophilic dermatosis
The etiology may be vasculitis caused by bacterial or fungal antigens and corresponding antibodies forming rabbit disease complexes.
13.Erythema nodosum
Mostly induced by streptococcal and Mycobacterium tuberculosis infection, also seen in leprosy out of BehCet’s disease and drugs.