dermatologic Disorders

History and physical examination are adequate for diagnosing many skin lesions. Some require biopsy or other testing.

topical dermatologic treatments are grouped according to their therapeutic functions and include

一个cne vulgaris is the formation of comedones, papules, pustules, nodules, and/or cysts as a result of obstruction and inflammation of pilosebaceous units (hair follicles and their accompanying sebaceous gland). Acne develops on the face and upper trunk. It most often affects adolescents. Diagnosis is by examination. Treatment, based on severity, can involve a variety of topical and systemic agents directed at reducing sebum production, comedone formation, inflammation, and bacterial counts and at normalizing keratinization.

bacterial skin infections can be classified as skin and soft tissue infections (SSTI) and acute bacterial skin and skin structure infections (ABSSSI). SSTI include

一个typical moles are benign melanocytic nevi with irregular and ill-defined borders, variegated colors usually of brown and tan tones, and macular or papular components. Patients with atypical moles have an increased risk of melanoma. Management is by close clinical monitoring and biopsy of highly atypical or changed lesions. Patients should reduce sun exposure and conduct regular self-examinations for new moles or changes in existing ones.

大桶升高，直径≥10毫米的流体水泡升高。

皮肤癌是最常见的癌症类型commonly develops in sun-exposed areas of skin. The incidence is highest among outdoor workers, sportsmen, and sunbathers and is inversely related to the amount of melanin skin pigmentation; fair-skinned people are most susceptible. Skin cancers may also develop years after therapeutic x-rays or exposure to carcinogens (eg, arsenic ingestion).

Calluses and corns are circumscribed areas of hyperkeratosis at a site of intermittent pressure or friction. Calluses are more superficial, cover broader areas of skin, and are usually asymptomatic. Corns are deeper, more focal, and frequently painful. Diagnosis is by appearance. Treatment is with manual abrasion with or without keratolytics. Prevention involves altering biomechanics, such as changing footwear. Rarely, surgery is required.

the meaning of the word "dermatitis" is inflammation of the skin. However, in clinical dermatology, dermatitis is used to describe a variety of different skin conditions that share the same inflammatory reaction pattern with similar clinical manifestations.

念珠菌病是皮肤和粘膜感染Candida物种，最常见Candida albicans. Infections can occur anywhere and are most common in skinfolds, digital web spaces, genitals, cuticles, and oral mucosa. Symptoms and signs vary by site. Diagnosis is by clinical appearance and/or potassium hydroxide wet mount of skin scrapings. Treatment is with drying agents and antifungals.

一个lopecia is defined as loss of hair from the body. Hair loss is often a cause of great concern to the patient for cosmetic and psychologic reasons, but it can also be an important sign of systemic disease.

the immune system plays a significant role in most skin disorders. The following skin disorders can be primarily characterized by a hypersensitivity or other type of reaction, be it to a drug, infection, or cancer:

一个variety of disorders can affect nails, including deformities, trauma, infections of the nail, paronychia, retronychia, and ingrown toenails. Nail changes may occur in many systemic conditions and genetic syndromes or result from trauma.

bedbug bites are usually painless but cause reactions, often pruritic, in susceptible patients. Diagnosis is clinical. Treament is symptomatic treatment of bites and chemical and physical eradication of bedbugs.

黑色素是负责皮肤，头发和眼睛虹膜颜色的褐色色素。它是由黑素细胞产生的。大多数人都有类似的黑素细胞，并且人类皮肤的颜色阴影范围是由于产生的黑色素量而不是黑素细胞的数量所致。黑色素有不同的亚型，皮肤中的主要成型是

压力损伤是坏死和经常溃疡的区域（也称为压疮），在骨头突出和外部硬表面之间被压缩软组织。它们是由不脱落的机械压力与摩擦，剪切力和水分结合使用的。危险因素包括年龄> 65岁，循环和组织灌注受损，固定，营养不良，感觉降低和尿失禁。严重程度从不可抑制的皮肤红斑到全厚性皮肤损失，并具有广泛的软组织坏死。诊断是临床的。预后非常适合早期受伤。被忽视和后期伤害构成严重感染的风险，难以治愈。治疗包括减压，避免摩擦和剪切力以及勤奋的伤口护理。有时，需要皮肤移植物或心肌皮瓣来促进愈合。

银屑病是一种炎性疾病清单s most commonly as well-circumscribed, erythematous papules and plaques covered with silvery scales. Multiple factors contribute, including genetics. Common triggers include trauma, infection, and certain drugs. Symptoms are usually minimal, but mild to severe itching may occur. Cosmetic implications may be major. Some people develop severe disease with painful arthritis (psoriatic arthritis). Diagnosis is based on appearance and distribution of lesions. Treatment can include topical treatments (eg, emollients, vitamin D3 analogs, retinoids, coal tar, anthralin, corticosteroids), phototherapy, and, when severe, systemic drugs (eg, methotrexate, oral retinoids, cyclosporine, immunomodulatory agents [biologics]).

the skin may respond to sunlight with chronic (eg, dermatoheliosis [photoaging], actinic keratosis) or acute (eg, photosensitivity, sunburn) changes.

there are two types of sweat glands: apocrine and eccrine.

molluscum contagiosum is characterized by clusters of pink, dome-shaped, smooth, waxy, or pearly and umbilicated papules 2 to 5 mm in diameter caused by molluscum contagiosum virus, a poxvirus. Diagnosis is based on clinical appearance. Treatment aims to prevent spread or remove cosmetically unacceptable lesions and can include mechanical methods (eg, curettage, cryosurgery) and topical irritants (eg, imiquimod, cantharidin, tretinoin).