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. 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.
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.
Trichobacteriosis axillaris is a superficial bacterial colonization of the hair shafts in sweat gland–bearing areas, such as the armpits and the groin. It is a trivial disease of worldwide occurrence that is believed to be caused by the genus Corynebacteria.
Cutis laxa or pachydermatocele is a group of rare connective tissue disorders in which the skin becomes inelastic and hangs loosely in folds.
Eosinophilic folliculitis is an itchy rash with an unknown cause that is most common among individuals with HIV, though it can occur in HIV-negative individuals where it is known by the eponym Ofuji disease. EF consists of itchy red bumps (papules) centered on hair follicles and typically found on the upper body, sparing the abdomen and legs. The name eosinophilic folliculitis refers to the predominant immune cells associated with the disease (eosinophils) and the involvement of the hair follicles.
Florid cutaneous papillomatosis (FCP), is an obligate paraneoplastic syndrome.
Acrokeratoelastoidosis of Costa is a familial condition characterized by multiple keratotic papules on the dorsum of the hands and feet, palms, soles, in which electron microscopy shows rarified, abnormal elastic tissue.
Pustulosis palmaris et plantaris is a chronic recurrent pustular dermatosis localized on the palms and soles only, characterized histologically by intraepidermal pustules filled with neutrophils. It can occur as part of the SAPHO syndrome.
Alezzandrini syndrome is a very rare syndrome characterized by a unilateral degenerative retinitis, followed after several months by ipsilateral vitiligo on the face and ipsilateral poliosis. Deafness may also be present.
Porokeratosis is a specific disorder of keratinization that is characterized histologically by the presence of a cornoid lamella, a thin column of closely stacked, parakeratotic cells extending through the stratum corneum with a thin or absent granular layer.
Keratoderma climactericum is a skin condition characterized by hyperkeratosis of the palms and soles beginning at about the time of menopause.
A preauricular sinus is a common congenital malformation characterized by a nodule, dent or dimple located anywhere adjacent to the external ear. Frequency of preauricular sinus differs depending the population: 0.1–0.9% in the US, 0.9% in the UK, and 4–10% in Asia and parts of Africa.
Doucas and Kapetanakis pigmented purpura is a skin condition characterized by scaly and eczematous patches, which also have petechiae and hemosiderin staining.
Sycosis vulgaris is a cutaneous condition characterized by a chronic infection of the chin or bearded region. The irritation is caused by a deep infection of hair follicles, often by species of Staphylococcus or Propionibacterium bacteria. Asymptomatic or painful and tender erythematous papules and pustules may form around coarse hair in the beard or the back of the neck.
Cobb syndrome is a rare congenital disorder characterized by visible skin lesions with underlying spinal angiomas or arteriovenous malformations (AVMs). The skin lesions of Cobb syndrome typically are present as port wine stains or angiomas, but reports exist of angiokeratomas, angiolipomas, and lymphangioma circumscriptum. The intraspinal lesions may be angiomas or AVMs and occur at levels of the spinal cord corresponding to the affected skin dermatomes. They may in turn produce spinal cord dysfunction and weakness or paralysis.
Eruptive pseudoangiomatosis is a cutaneous condition characterized by the sudden appearance of 2- to 4-mm blanchable red papules.
Balanitis plasmacellularis is a cutaneous condition characterized by a benign inflammatory skin lesion characterized histologically by a plasma cell infiltrate.
Symmetrical drug-related intertriginous and flexural exanthema (SDRIFE), more popularly known as baboon syndrome because of its resemblance to the distinctive red buttocks displayed by female baboons, is a systemic contact dermatitis characterized by well-demarcated patches of erythema distributed symmetrically on the buttocks. The cause of the syndrome may be drug-related, i.e. induced by systemic administration of hydroxyzine penicillin, iodinated radio contrast media and others.
Acute cutaneous lupus erythematosus is a cutaneous condition characterized by a bilateral malar rash and lesions that tend to be transient, and that follow sun exposure. The acute form is distinct from chronic and subacute cutaneous lupus erythematosus, which may have different types of skin lesions. Cutaneous lupus erythematosus is associated with both lupus erythematosus-specific lesions and cutaneous manifestations that are not specific to lupus erythematosus, such as oral ulcers and urticaria. Because of the diagnostic criteria used to diagnose systemic lupus erythematosus, a patient with only cutaneous manifestations may be diagnosed with the systemic form of the disease.
