| Parapsoriasis | |
|---|---|
| Specialty | Dermatology  |
Parapsoriasis refers to one of a group of skin disorders that are characterized primarily by their resemblance to psoriasis (red, scaly lesions), rather than by their underlying cause.
Neoplasms can develop from parapsoriasis. [1] For example, it can develop into cutaneous T-cell lymphoma.
The word "parapsoriasis" was formed in 1902. [2]
The parapsoriasis groups, described and debated for nearly a century, has spawned a confusing nomenclature. There are some authors who prefer to limit the term "parapsoriasis" to large- and small-plaque variants only. [2] However, the following classification scheme is now generally accepted: [3] : 450
Pityriasis lichenoides et varioliformis acuta is a disease of the immune system. It is the more severe version of pityriasis lichenoides chronica. The disease is characterized by rashes and small lesions on the skin. The disease is more common in males and usually occurs in young adulthood, although it has been seen in every age group and every race. It is possible for the disease to go into remission for short periods of time or forever.
Tinea versicolor is a condition characterized by a skin eruption on the trunk and proximal extremities. The majority of tinea versicolor is caused by the fungus Malassezia globosa, although Malassezia furfur is responsible for a small number of cases. These yeasts are normally found on the human skin and become troublesome only under certain circumstances, such as a warm and humid environment, although the exact conditions that cause initiation of the disease process are poorly understood.
Lichen planus (LP) is a chronic inflammatory and immune-mediated disease that affects the skin, nails, hair, and mucous membranes. It is not an actual lichen, and is only named that because it looks like one. 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.
Pityriasis rosea is a type of skin rash. Classically, it begins with a single red and slightly scaly area known as a "herald patch". This is then followed, days to weeks later, by an eruption of many smaller scaly spots; pinkish with a red edge in people with light skin and greyish in darker skin. About 20% of cases show atypical deviations from this pattern. It usually lasts less than three months and goes away without treatment. Sometimes malaise or a fever may occur before the start of the rash or itchiness, but often there are few other symptoms.
Palmoplantar keratodermas are a heterogeneous group of disorders characterized by abnormal thickening of the stratum corneum of the palms and soles.
Mycosis fungoides, also known as Alibert-Bazin syndrome or granuloma fungoides, is the most common form of cutaneous T-cell lymphoma. It generally affects the skin, but may progress internally over time. Symptoms include rash, tumors, skin lesions, and itchy skin.
Cutaneous T-cell lymphoma (CTCL) is a class of non-Hodgkin lymphoma, which is a type of cancer of the immune system. Unlike most non-Hodgkin lymphomas, CTCL is caused by a mutation of T cells. The cancerous T cells in the body initially migrate to the skin, causing various lesions to appear. These lesions change shape as the disease progresses, typically beginning as what appears to be a rash which can be very itchy and eventually forming plaques and tumors before spreading to other parts of the body.
Pityriasis rubra pilaris refers to a group of chronic disorders characterized by reddish orange, scaling plaques and keratotic follicular papules. Symptoms may include reddish-orange patches on the skin, severe flaking, uncomfortable itching, thickening of the skin on the feet and hands, and thickened bumps around hair follicles. For some, early symptoms may also include generalized swelling of the legs, feet and other parts of the body. PRP has a varied clinical progression and a varied rate of improvement. There is currently no known cause or cure for PRP.
Pityriasis commonly refers to flaking of the skin. The word comes from the Greek πίτυρον "bran".
Erythroderma is an inflammatory skin disease with redness and scaling that affects nearly the entire cutaneous surface. This term applies when 90% or more of the skin is affected.
Pityriasis lichenoides chronica is an uncommon, idiopathic, acquired dermatosis, characterized by evolving groups of erythematous, scaly papules that may persist for months.
Pityriasis alba is a skin condition, a type of dermatitis, commonly seen in children and young adults as dry, fine-scaled, pale patches on the face. It is self-limiting and usually only requires use of moisturizer creams.
Epidermodysplasia verruciformis (EV) is a skin condition characterised by warty skin lesions. It results from an abnormal susceptibility to HPV infection (HPV) and is associated with a high lifetime risk of squamous cell carcinomas in skin. It generally presents with scaly spots and small bumps particularly on the hands, feet, face and neck; typically beginning in childhood or in a young adult. The bumps tend to be flat, grow in number and then merge to form plaques. On the trunk, it typically appears like pityriasis versicolor; lesions there being slightly scaly and tan, brown, red or looking pale. On the elbows, it may appear like psoriasis. On the forehead, neck and trunk, the lesions may appear like seborrheic keratosis.
Lymphomatoid papulosis (LyP) is a rare skin disorder.
A papulosquamous disorder is a condition which presents with both papules and scales, or both scaly papules and plaques.
Pityriasis amiantacea is an eczematous condition of the scalp in which thick tenaciously adherent scale infiltrates and surrounds the base of a group of scalp hairs. It does not result in scarring or alopecia.
Large plaque parapsoriasis are skin lesions that may be included in the modern scheme of cutaneous conditions described as parapsoriasis. These lesions, called plaques, may be irregularly round-shaped to oval and are 10 cm (4 in) or larger in diameter. They can be very thin plaques that are asymptomatic or mildly pruritic. Large-plaque parapsoriasis is a common associate of retiform parapsoriasis, can be accompanied by poikiloderma vasculare atrophicans, and can in rare occasions be a precursor to cutaneous T-cell lymphoma.
Small plaque parapsoriasis characteristically occurs with skin lesions that are round, oval, discrete patches or thin plaques, mainly on the trunk.
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.
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