A skin tag, or acrochordon, is a small benign tumor that forms primarily in areas where the skin forms creases, such as the neck, armpit and groin. They may also occur on the face, usually on the eyelids. Though tags up to 13 mm long have been seen, they are typically the size of a grain of rice. The surface of an acrochordon may be smooth or irregular in appearance and is often raised from the surface of the skin on a fleshy stalk called a peduncle. Microscopically, an acrochordon consists of a fibrovascular core, sometimes also with fat cells, covered by an unremarkable epidermis. However, tags may become irritated by shaving, clothing, jewelry or eczema.
Leishmaniasis is a wide array of clinical manifestations caused by protozoal parasites of the Trypanosomatida genus Leishmania. It is generally spread through the bite of phlebotomine sandflies, Phlebotomus and Lutzomyia, and occurs most frequently in the tropics and sub-tropics of Africa, Asia, the Americas, and southern Europe. The disease can present in three main ways: cutaneous, mucocutaneous, or visceral. The cutaneous form presents with skin ulcers, while the mucocutaneous form presents with ulcers of the skin, mouth, and nose. The visceral form starts with skin ulcers and later presents with fever, low red blood cell count, and enlarged spleen and liver.
Panniculitis is a group of diseases whose hallmark is inflammation of subcutaneous adipose tissue. Symptoms include tender skin nodules, and systemic signs such as weight loss and fatigue.
Lichen planus (LP) is a chronic inflammatory and autoimmune disease that affects the skin, nails, hair, and mucous membranes. It is not an actual lichen, but is named for its appearance. It is characterized by polygonal, flat-topped, violaceous papules and plaques with overlying, reticulated, fine white scale, commonly affecting dorsal hands, flexural wrists and forearms, trunk, anterior lower legs and oral mucosa. The hue may be gray-brown in people with darker skin. Although there is a broad clinical range of LP manifestations, the skin and oral cavity remain as the major sites of involvement. The cause is unknown, but it is thought to be the result of an autoimmune process with an unknown initial trigger. There is no cure, but many different medications and procedures have been used in efforts to control the symptoms.
Hyperpigmentation, also known as dark spots on the skin, is the darkening of an area of skin or nails caused by increased melanin.
Tuberculosis verrucosa cutis is a rash of small, red papules and nodules in the skin that may appear two to four weeks after inoculation by Mycobacterium tuberculosis in a previously infected and immunocompetent individual.
Cutaneous larva migrans is a skin disease in humans, caused by the larvae of various nematode parasites of the hookworm family (Ancylostomatidae). The parasites live in the intestines of dogs, cats, and wild animals; they should not be confused with other members of the hookworm family for which humans are definitive hosts, namely Ancylostoma duodenale and Necator americanus.
Urticaria pigmentosa (also known as generalized eruption of cutaneous mastocytosis (childhood type) ) is the most common form of cutaneous mastocytosis. It is a rare disease caused by excessive numbers of mast cells in the skin that produce hives or lesions on the skin when irritated.
Cutaneous leishmaniasis is the most common form of leishmaniasis affecting humans. It is a skin infection caused by a single-celled parasite that is transmitted by the bite of a phlebotomine sand fly. There are about thirty species of Leishmania that may cause cutaneous leishmaniasis.
A spider angioma or spider naevus, also nevus araneus, is a type of telangiectasis found slightly beneath the skin's surface, often containing a central red spot and deep reddish extensions which radiate outwards like a spider's web or a spider's legs. They are common and often benign, presenting in around 10–15% of healthy adults and young children. However, having more than three spider angiomas is likely to be abnormal and may be a sign of liver disease and/or hepatitis C ; it also suggests the probability of esophageal varices.
Angiokeratoma is a benign cutaneous lesion of capillaries, resulting in small marks of red to blue color and characterized by hyperkeratosis. Angiokeratoma corporis diffusum refers to Fabry's disease, but this is usually considered a distinct condition.
Leishmania major is a species of parasite found in the genus Leishmania, and is associated with the disease zoonotic cutaneous leishmaniasis. L. major is an intracellular pathogen which infects the macrophages and dendritic cells of the immune system. Though Leishmania species are found on every continent aside from Antarctica, Leishmania major is found only in the Eastern Hemisphere, specifically in Northern Africa, the Middle East, Northwestern China, and Northwestern India.
Lupus erythematosus is a collection of autoimmune diseases in which the human immune system becomes hyperactive and attacks healthy tissues. Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs. The most common and most severe form is systemic lupus erythematosus.
In medicine, a drug eruption is an adverse drug reaction of the skin. Most drug-induced cutaneous reactions are mild and disappear when the offending drug is withdrawn. These are called "simple" drug eruptions. However, more serious drug eruptions may be associated with organ injury such as liver or kidney damage and are categorized as "complex". Drugs can also cause hair and nail changes, affect the mucous membranes, or cause itching without outward skin changes.
Subacute cutaneous lupus erythematosus is a clinically distinct subset of cases of lupus erythematosus that is most often present in white women aged 15 to 40, consisting of skin lesions that are scaly and evolve as poly-cyclic annular lesions or plaques similar to those of plaque psoriasis.
Cutaneous small-vessel vasculitis (CSVV) is inflammation of small blood vessels, usually accompanied by small lumps beneath the skin. The condition is also known as hypersensitivity vasculitis, cutaneous leukocytoclastic vasculitis, hypersensitivity angiitis, cutaneous leukocytoclastic angiitis, cutaneous necrotizing vasculitis and cutaneous necrotizing venulitis,
Cutaneous lymphoid hyperplasia refers to a groups of benign cutaneous disorders characterized by collections of lymphocytes, macrophages, and dendritic cells in the skin. Conditions included in this groups are:
Poikiloderma vasculare atrophicans (PVA), is a cutaneous condition characterized by hypo- or hyperpigmentation, telangiectasia and skin atrophy. Other names for the condition include prereticulotic poikiloderma and atrophic parapsoriasis. The condition was first described by pioneer American pediatrician Abraham Jacobi in 1906. PVA causes areas of affected skin to appear speckled red and inflamed, yellowish and/or brown, gray or grayish-black, with scaling and a thinness that may be described as "cigarette paper". On the surface of the skin, these areas may range in size from small patches, to plaques, to neoplasms.
Pseudomonal pyoderma is a cutaneous condition, a superficial infection of the skin with P. aeruginosa. The skin can have a 'mousy' odor. It presents typically on the feet with macerated 'moth-eaten' appearance, green-blue purulence, and eroded borders.
