Clinically, three distinct patterns of palmoplantar keratoderma may be identified: diffuse, focal, and punctate.

Diffuse palmoplantar keratoderma is a type of palmoplantar keratoderma that is characterized by an even, thick, symmetric hyperkeratosis over the whole of the palm and sole, usually evident at birth or in the first few months of life. Restated, diffuse palmoplantar keratoderma is an autosomal dominant disorder in which hyperkeratosis is confined to the palms and soles. The two major types can have a similar clinical appearance:

- "Diffuse epidermolytic palmoplantar keratoderma" (also known as "Palmoplantar keratoderma cum degeneratione granulosa Vörner," "Vörner's epidermolytic palmoplantar keratoderma", and "Vörner keratoderma") is one of the most common patterns of palmoplantar keratoderma, an autosomal dominant condition that presents within the first few months of life, characterized by a well-demarcated, symmetric thickening of palms and soles, often with a "dirty" snakeskin appearance due to underlying epidermolysis.

- "Diffuse nonepidermolytic palmoplantar keratoderma" (also known as "Diffuse orthohyperkeratotic keratoderma," "Hereditary palmoplantar keratoderma," "Keratosis extremitatum progrediens," "Keratosis palmoplantaris diffusa circumscripta," "Tylosis," "Unna–Thost disease", and "Unna–Thost keratoderma") is inherited as an autosomal dominant condition and is present from infancy, characterized by a well-demarcated, symmetric, often "waxy" keratoderma involving the whole of the palms and soles.

Schöpf–Schulz–Passarge syndrome (also known as "eyelid cysts, palmoplantar keratoderma, hypodontia, and hypotrichosis") is an autosomal recessive condition with diffuse symmetric palmoplantar keratoderma, with the palmoplantar keratoderma and fragility of the nails beginning around age 12. In addition to palmoplantar keratoderma, other symptoms include hypodontia, hypotrichosis, nail dystrophies, and eyelid cysts (apocrine hidrocystomas). Patients may also develop syringofibroadenoma and squamous cell carcinomas.

It was characterized in 1971.

It has been associated with WNT10A.

Bowen's disease typically presents as a gradually enlarging, well-demarcated red colored plaque with an irregular border and surface crusting or scaling. Bowen's disease may occur at any age in adults, but is rare before the age of 30 years; most patients are aged over 60. Any site may be affected, although involvement of palms or soles is uncommon. Bowen's disease occurs predominantly in women (70–85% of cases). About 60–85% of patients have lesions on the lower leg, usually in previously or presently sun-exposed areas of skin.

This is a persistent, progressive, unelevated, red, scaly or crusted plaque which is due to an intraepidermal carcinoma and is potentially malignant. The lesions may occur anywhere on the skin surface, including on mucosal surfaces. Freezing, cauterization, or diathermy coagulation is often effective treatment. Pathomorphologic study of tissue sampling revealed: polymorphism of spiny epithelial cells has progressed into atypism; increased mitosis; giant and multinucleate cells; acanthosis; hyperkeratosis and parakeratosis; basal membrane and basal layer are retained.

Acrokeratosis verruciformis (also known as "Acrokeratosis verruciformis of Hopf" is a rare autosomal dominant disorder appearing at birth or in early childhood, characterized by skin lesions that are small, verrucous, flat papules resembling warts along with palmoplantar punctate keratoses and pits. However sporadic forms, whose less than 10 cases have been reported, presents at a later age, usually after the first decade and generally lack palmoplantar keratoses.

Whether acrokeratosis verruciformis and Darier disease are related or distinct entities has been controversial, like Darier's disease, it is associated with defects in the ATP2A2 gene. however the specific mutations found in the ATP2A2 gene in acrokeratosis verruciformis have never been found in Darier's disease.

Hidrotic ectodermal dysplasia 2, or Clouston syndrome (referred to as HED2 throughout this entry) is characterized by partial or total alopecia, dystrophy of the nails, hyperpigmentation of the skin (especially over the joints), and clubbing of the fingers. Sparse scalp hair and dysplastic nails are seen early in life. In infancy, scalp hair is wiry, brittle, patchy, and pale; progressive hair loss may lead to total alopecia by puberty. The nails may be milky white in early childhood; they gradually become dystrophic, thick, and distally separated from the nail bed. Palmoplantar keratoderma may develop during childhood and increases in severity with age. The clinical manifestations are highly variable even within the same family.

Most cases of leukoplakia cause no symptoms, but infrequently there may be discomfort or pain. The exact appearance of the lesion is variable. Leukoplakia may be white, whitish yellow or grey. The size can range from a small area to much larger lesions. The most common sites affected are the buccal mucosa, the labial mucosa and the alveolar mucosa, although any mucosal surface in the mouth may be involved. The clinical appearance, including the surface texture and color, may be homogenous or non-homogenous (see: classification). Some signs are generally associated with a higher risk of cancerous changes (see: prognosis).

Leukoplakia may rarely be associated with esophageal carcinoma.

Causes of Bowen's disease include solar damage, arsenic, immunosuppression (including AIDS), viral infection (human papillomavirus or HPV), chronic skin injury, and other dermatoses.

In the context of lesions of the mucous membrane lining of the bladder, leukoplakia is a historic term used to describe a visualized white patch which histologically represents keratinization in an area of squamous metaplasia. The symptoms may include frequency, suprapubic pain (pain felt above the pubis), hematuria (blood in the urine), dysuria (difficult urination or pain during urination), urgency, and urge incontinence. The white lesion may be seen during cystoscopy, where it appears as a whitish-gray or yellow lesion, on a background of inflamed urothelium and there may be floating debris in the bladder. Leukoplakia of the bladder may undergo cancerous changes, so biopsy and long term follow up are usually indicated.

Common symptoms include:

- Excess keratin in nail beds and thickening of the nails

- Hyperkeratosis on hands and feet

- Oral lesions that look like thick white plaques

- Steatocystoma multiplex

- Pain

- Blisters

The skin may be lightly pigmented. Skin sustaining injury may grow back permanently hypo-pigmented. In some cases, red or brown pigmentation may be present. Skin can be prone to rashes or infections and can be thick over the palms and soles. Care must be taken to prevent cracking, bleeding, and infection.

Fingernails and toenails may be thick, abnormally shaped, discolored, ridged, slow-growing, or brittle. The cuticles may be prone to infections.

Hypotrichosis–acro-osteolysis–onychogryphosis–palmoplantar keratoderma–periodontitis syndrome (also known as "HOPP syndrome") is a cutaneous condition characterized by a prominent palmoplantar keratoderma.

Ectodermal dysplasia with corkscrew hairs is a skin condition with salient features including exaggerated pili torti, scalp keloids, follicular plugging, keratosis pilaris, xerosis, eczema, palmoplantar keratoderma, syndactyly, onchodysplasia, and conjunctival neovascularization.

The symptoms of ichthyosis hystrix Curth-Macklin are similar to epidermolytic hyperkeratosis (NPS-2 type) but there is no blistering and the hyperkeratosis is verrucous or spine-like. The hyperkeratosis is brown-grey in colour and is most obvious on the arms and legs. It is an autosomal dominant condition and can be caused by errors to the KRT1 gene. It is named after Helen Ollendorff Curth (1899-1982), a German-Jewish dermatologist, and Madge Thurlow Macklin (1893–1962), an American medical geneticist, and is one of the first syndromes named after two women.

Ichthyosis hystrix is a group of rare skin disorders in the ichthyosis family of skin disorders characterized by massive hyperkeratosis with an appearance like spiny scales. This term is also used to refer to a type of epidermal nevi with extensive bilateral distribution.

Clouston's hidrotic ectodermal dysplasia (also known as "Alopecia congenita with keratosis palmoplantaris," "Clouston syndrome," "Fischer–Jacobsen–Clouston syndrome," "Hidrotic ectodermal dysplasia," "Keratosis palmaris with drumstick fingers," and "Palmoplantar keratoderma and clubbing") is caused by mutations in a connexin gene, GJB6 or connexin-30, characterized by scalp hair that is wiry, brittle, and pale, often associated with patchy alopecia.

Meleda disease (MDM) or "mal de Meleda", also called Mljet disease, keratosis palmoplantaris and transgradiens of Siemens, (also known as "Acral keratoderma," "Mutilating palmoplantar keratoderma of the Gamborg-Nielsen type," "Palmoplantar ectodermal dysplasia type VIII", and "Palmoplantar keratoderma of the Norrbotten type") is an extremely rare autosomal recessive congenital skin disorder in which dry, thick patches of skin develop on the soles of the hands and feet, a condition known as palmoplantar hyperkeratosis.

The differential diagnosis is quite extensive and includes

- Buschke–Fischer–Brauer disease

- Curth–Macklin ichthyosis

- Gamborg Nielsen syndrome

- Greither disease

- Haber syndrome

- Hereditary punctate palmoplantar keratoderma

- Jadassohn–Lewandowsky syndrome

- Keratosis follicularis spinulosa decalvans

- Keratosis linearis with ichthyosis congenital and sclerosing keratoderma syndrome

- Meleda disease

- Mucosa hyperkeratosis syndrome

- Naegeli–Franceschetti–Jadassohn syndrome

- Naxos disease

- Olmsted syndrome

- Palmoplantar keratoderma and leukokeratosis anogenitalis

- Pandysautonomia

- Papillomatosis of Gougerot and Carteaud

- Papillon–Lefèvre syndrome

- Punctate porokeratotic keratoderma

- Richner–Hanhart syndrome

- Schöpf–Schulz–Passarge syndrome

- Unna Thost disease

- Vohwinkel syndrome

- Wong's dermatomyositis

Lelis syndrome it is a genetic disorder, a rare condition with dermatological and dental findings characterized by the association of ectodermal dysplasia (hypotrichosis and hypohidrosis) with acanthosis nigricans. Other clinical features may include palmoplantar hyperkeratosis, nail dystrophy, intellectual deficit, disturbances of skin pigmentation (perioral and periorbital hyperpigmentation, vitiligo, and perinevic leukoderma) and hypodontia. Transmission is autosomal recessive.

Naegeli–Franceschetti–Jadassohn syndrome (NFJS), also known as chromatophore nevus of Naegeli and Naegeli syndrome, is a rare autosomal dominant form of ectodermal dysplasia, characterized by reticular skin pigmentation, diminished function of the sweat glands, the absence of teeth and hyperkeratosis of the palms and soles. One of the most striking features is the absence of fingerprint lines on the fingers.

Naegeli syndrome is similar to dermatopathia pigmentosa reticularis, both of which are caused by a specific defect in the keratin 14 protein.

Myrmecia is one of the three types of warts that occurs on the skin on the hands and feet (palmoplantar). It is induced by human papilloma virus type 1 (HPV1). They occur on the palms of the hands, soles of the feet, and on the sides of the fingers and toes. The histology is abundant eosinophilic inclusion bodies associated with HPV1 E4 gene products. It was studied as far back as 42 B.C. - 37 A.D. by Aulus Cornelius Celsus.

Howel–Evans syndrome is an extremely rare condition involving thickening of the skin in the palms of the hands and the soles of the feet (hyperkeratosis). This familial disease is associated with a high lifetime risk of esophageal cancer. For this reason, it is sometimes known as tylosis with oesophageal cancer (TOC).

The condition is inherited in an autosomal dominant manner, and it has been linked to a mutation in the "RHBDF2" gene. It was first described in 1958.

Haim–Munk syndrome (also known as "palmoplantar keratoderma with periodontitis and arachnodactyly and acro-osteolysis") is a cutaneous condition caused by a mutation in the cathepsin C gene. It was named after Dr. Salim Haim and Dr. Munk.

Focal palmoplantar and gingival keratosis is a rare autosomal dominant disease whose clinical features, and in particular, pathologic alterations and molecular mechanisms remains to be well defined.