A birthmark is a congenital, benign irregularity on the skin which is present at birth or appears shortly after birth—usually in the first month. Birthmarks can occur anywhere on the skin. They are caused by overgrowth of blood vessels, melanocytes, smooth muscle, fat, fibroblasts, or keratinocytes.
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.
Calcinosis cutis is an uncommon condition marked by calcium buildup in the skin and subcutaneous tissues. Calcinosis cutis can range in intensity from little nodules in one area of the body to huge, crippling lesions affecting a vast portion of the body. Five kinds of the condition are typically distinguished: calciphylaxis, idiopathic calcification, iatrogenic calcification, dystrophic calcification, and metastatic calcification.
Hypertrichosis is an abnormal amount of hair growth over the body. The two distinct types of hypertrichosis are generalized hypertrichosis, which occurs over the entire body, and localized hypertrichosis, which is restricted to a certain area. Hypertrichosis can be either congenital or acquired later in life. The excess growth of hair occurs in areas of the skin with the exception of androgen-dependent hair of the pubic area, face, and axillary regions.
Hyperkeratosis is thickening of the stratum corneum, often associated with the presence of an abnormal quantity of keratin, and is usually accompanied by an increase in the granular layer. As the corneum layer normally varies greatly in thickness in different sites, some experience is needed to assess minor degrees of hyperkeratosis.
Aplasia is a birth defect where an organ or tissue is wholly or largely absent. It is caused by a defect in a developmental process.
Cutis laxa or pachydermatocele is a group of rare connective tissue disorders in which the skin becomes inelastic and hangs loosely in folds.
Cutis marmorata telangiectatica congenita (CMTC) is a rare congenital vascular disorder that usually manifests in affecting the blood vessels of the skin. The condition was first recognized and described in 1922 by Cato van Lohuizen, a Dutch pediatrician whose name was later adopted in the other common name used to describe the condition – Van Lohuizen syndrome. CMTC is also used synonymously with congenital generalized phlebectasia, nevus vascularis reticularis, congenital phlebectasia, livedo telangiectatica, congenital livedo reticularis and Van Lohuizen syndrome.
Extramammary Paget's disease (EMPD) is a rare and slow-growing malignancy which occurs within the epithelium and accounts for 6.5% of all Paget's disease. The clinical presentation of this disease is similar to the characteristics of mammary Paget's disease (MPD). However, unlike MPD, which occurs in large lactiferous ducts and then extends into the epidermis, EMPD originates in glandular regions rich in apocrine secretions outside the mammary glands. EMPD incidence is increasing by 3.2% every year, affecting hormonally-targeted tissues such as the vulva and scrotum. In women, 81.3% of EMPD cases are related to the vulva, while for men, 43.2% of the manifestations present at the scrotum.
Anetoderma is a benign but uncommon disorder that causes localized areas of flaccid or herniated sac-like skin due to a focal reduction of dermal elastic tissue. Anetoderma is subclassified as primary anetoderma, secondary anetoderma, iatrogenic anetoderma of prematurity, congenital anetoderma, familial anetoderma, and drug-induced anetoderma.
Aplasia cutis congenita is a rare disorder characterized by congenital absence of skin. Ilona J. Frieden classified ACC in 1986 into 9 groups on the basis of location of the lesions and associated congenital anomalies. The scalp is the most commonly involved area with lesser involvement of trunk and extremities. Frieden classified ACC with fetus papyraceus as type 5. This type presents as truncal ACC with symmetrical absence of skin in stellate or butterfly pattern with or without involvement of proximal limbs. It is the most common congenital cicatricial alopecia, and is a congenital focal absence of epidermis with or without evidence of other layers of the skin.
Alopecia mucinosa, also known as Follicular mucinosis, Mucinosis follicularis, Pinkus' follicular mucinosis, and Pinkus' follicular mucinosis–benign primary form, is a skin disorder that generally presents, but not exclusively, as erythematous plaques or flat patches without hair primarily on the scalp, neck and face. This can also be present on the body as a follicular mucinosis and may represent a systemic disease.
Osteoma cutis is a cutaneous condition characterized by the presence of bone within the skin in the absence of a preexisting or associated lesion. Osteoma cutis often manifests as solid, varying-sized, skin-colored subcutaneous nodules.
Rosenthal–Kloepfer syndrome, is a cutaneous condition characterized by abnormal growth of bone and skin, coupled with clouding of the cornea. It was described in 1962. Another name for the condition is Acromegaly-cutis verticis gyrata-corneal leukoma syndrome.
Lipedematous alopecia is a disorder characterized by a thick boggy scalp and hair loss. Symptoms include pain, puritis, headaches, and paresthesia. The cause of lipedematous alopecia is unknown. The diagnosis is made my excluding other disorders, MRI, CT scan, and histopathology. There is no accepted treatment however surgical debunking has been found effective.
Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) or Reed's syndrome is rare autosomal dominant disorder associated with benign smooth muscle tumors and an increased risk of renal cell carcinoma. It is characterised by multiple cutaneous leiomyomas and, in women, uterine leiomyomas. It predisposes individuals to renal cell cancer, an association denominated hereditary leiomyomatosis and renal cell cancer. It is also associated with increased risk of uterine leiomyosarcoma. The syndrome is caused by a mutation in the fumarate hydratase gene, which leads to an accumulation of fumarate. The inheritance pattern is autosomal dominant and screening can typically begin in childhood.
Beare–Stevenson cutis gyrata syndrome is a rare genetic disorder characterized by craniosynostosis and a specific skin abnormality, called cutis gyrata, characterized by a furrowed and wrinkled appearance ; thick, dark, velvety areas of skin are sometimes found on the hands and feet and in the groin.
Stasis papillomatosis is a disease characterized by chronic congestion of the extremities, with blood circulation interrupted in a specific area of the body. A consequence of this congestion and inflammation is long-term lymphatic obstruction (lymphedema). It is also typically characterized by the appearance of numerous papules. Injuries can range from small to large plates composed of brown or pink, smooth or hyperkeratotic papules. The most typical areas where injuries occur are the back of the feet, the toes, the legs, and the area around a venous ulcer formed in the extremities, although the latter is the rarest of all. These injuries include pachydermia, lymphedema, lymphomastic verrucosis and elephantosis verrucosa. The disease can be either localized or generalized; the localized form makes up 78% of cases. Treatment includes surgical and pharmaceutical intervention; indications for partial removal include advanced fibrotic lymphedema and elephantiasis. Despite the existence of these treatments, chronic venous edema, which is a derivation of stasis papillomatosis, is only partially reversible. The skin is also affected and its partial removal may mean that the skin and the subcutaneous tissue are excised. A side effect of the procedure is the destruction of existing cutaneous lymphatic vessels. It also risks papillomatosis, skin necrosis and edema exacerbation.
Hypothyroidism is an endocrine disorder in which the thyroid gland fails to produce sufficient thyroid hormones. Hypothyroidism is one of the most common endocrinopathies in dogs. It is either acquired or congenital.
