Palmoplantar keratodermas are a heterogeneous group of disorders characterized by abnormal thickening of the palms and soles.

Autosomal recessive and dominant, X-linked, and acquired forms have all been described.

Usually, a common form of treatment for the condition is a type of hand cream which moisturises the hard skin. However, currently the condition is incurable.

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.

Individuals affected by certain ED syndromes cannot perspire. Their sweat glands may function abnormally or may not have developed at all because of inactive proteins in the sweat glands. Without normal sweat production, the body cannot regulate temperature properly. Therefore, overheating is a common problem, especially during hot weather. Access to cool environments is important.

Several studies have examined salivary flow rate in individuals and found parotid and submandibular salivary flow ranging from 5 to 15 times lower than average. This is consistent with the salivary glands being of ectodermal origin, although some findings have suggested that there is also mesodermal input.

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.

MDM is most common on the Dalmatian island of Mljet (or "Meleda"), thought to be because of a founder effect. It is of autosomal recessive inheritance. It may be caused by a mutation on the "SLURP1" gene, located on chromosome 8.

Treatment of manifestations: special hair care products to help manage dry and sparse hair; wigs; artificial nails; emollients to relieve palmoplantar hyperkeratosis.

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

PLS is characterized by periodontitis and palmoplantar keratoderma. The severe destruction of periodontium results in loss of most primary teeth by the age of 4 and most permanent teeth by age 14. Hyperkeratosis of palms and soles of feet appear in first few years of life. Destructions of periodontium follows almost immediately after the eruption of last molar tooth. The teeth are involved in roughly the same order in which they erupt.

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.

Papillon–Lefèvre syndrome (PLS), also known as palmoplantar keratoderma with periodontitis, is an autosomal recessive genetic disorder caused by a deficiency in cathepsin C.

A mutation in the KDSR gene has been reported to be associated with this condition. This gene encodes 3-ketodihydrosphingosine reductase, an enzyme in the ceramide synthesis pathway. The authors also reported that the use of systemic isotretinoin resulted in almost complete resolution of the lesions in two cases.

Two other reports suggest that isotretinoin may be of use.

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.

Pachyonychia congenita follows an autosomal dominant pattern of inheritance, which means the defective gene is located on an autosome, and only one copy of the gene is required to inherit the disorder from a parent who has the disorder. On average, 50% of the offspring of an affected person will inherit the disorder, regardless of gender.

Occasionally, however, a solitary case can emerge in a family with no prior history of the disorder due to the occurrence of a new mutation (often referred to as a sporadic or spontaneous mutation).

This includes erythrokeratodermia variabilis and loricrin keratoderma

Pachyonychia congenita may be divided into these types:

- Pachyonychia congenita type I (also known as "Jadassohn–Lewandowsky syndrome") is an autosomal dominant keratoderma that principally involves the plantar surfaces, but also with nails changes that may be evident at birth, but more commonly develop within the first few months of life.

- Pachyonychia congenita type II (also known as "Jackson–Lawler pachyonychia congenita" and "Jackson–Sertoli syndrome") is an autosomal dominant keratoderma presenting with a limited focal plantar keratoderma that may be very minor, with nails changes that may be evident at birth, but more commonly develop within the first few months of life.

Naxos disease (also known as "Diffuse non-epidermolytic palmoplantar keratoderma with woolly hair and cardiomyopathy," "Diffuse palmoplantar keratoderma with woolly hair and arrhythmogenic right ventricular cardiomyopathy firstly described in Naxos island by Dr Nikos Protonotarios," and "Naxos disease") is a cutaneous condition characterized by a palmoplantar keratoderma. The prevalence of the syndrome is about 1 person in 1000 in the Hellenic islands.

It has been associated with mutations in the genes encoding desmoplakin and plakoglobin.

Bart–Pumphrey syndrome (also known as "Palmoplantar keratoderma with knuckle pads and leukonychia and deafness") is a cutaneous condition characterized by hyperkeratoses (knuckle pads) over the metacarpophalangeal, proximal and distal interphalangeal joints.

It was characterized in 1967.

It can be associated with GJB2.

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.

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.

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.

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.

This condition is an autosomal recessive genetic disorder, which means the defective gene is located on an autosome, and both parents must carry one copy of the defective gene in order to have a child born with the disorder. Carriers of a recessive gene usually do not show any signs or symptoms of the disorder.

One form of ichthyosis lamellaris (LI1) is associated with a deficiency of the enzyme keratinocyte transglutaminase.

Genes involved include:

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.