Generality
Hyperkeratosis is a thickening of the epidermis, caused by a quantitative alteration of keratinocytes . The hyperproliferation of these cells - widespread or limited - results in more or less detected formations on the skin plane.
Hyperkeratosis mainly affects the dermatological field, but it can also be related to systemic morbid events .
In some cases, this disorder is the expression of an adaptive response of the epidermis, through which the skin becomes more resistant to continuous and prolonged mechanical stresses (this happens, for example, in the case of so-called callosities or "calluses") ). In practice, it is a defense mechanism that the body implements to protect the skin surface.
Other times, hyperkeratosis is the expression of local or systemic pathological processes, such as inflammation, infections (eg papilloma virus), chronic exposure to ultraviolet rays and metabolic disorders .
The treatment of hyperkeratosis varies depending on the underlying disease, but usually uses ointments, pastes or keratolytic solutions, which have the ability to remove, by softening them, the thickened portions of skin.
How the skin is made (in short)
The skin (or skin) appears as a thin fabric, covered with hair and small imperfections. In reality, this is composed of three main layers, each of which performs different functions and, in turn, are divided into further zones.
- Epidermis (most superficial part): it is the epithelial layer of the skin, which represents the external scaffold of this organ, as well as the skin component in direct contact with the environment. The epidermis consists of several "zones" (from the deepest layer to the surface: basal, thorny, grainy, shiny and horny) that reflect the life cycle of the epithelial cells present: the keratinocytes . In the epidermis, the stratum corneum is the most external cellular layer; this is formed from 20 to 30 cellular laminae, which resemble overlapping "tiles" ("horny scales") which determine the keratinization of the skin and its protection. The cells that form these laminae have no nucleus and have a hard consistency; each of these elements is destined to fall off and fall through flaking, to be replaced by new elements. The stratum corneum is the more often the more it is exposed to mechanical insults: its thickness is very accentuated, for example, on the palms of the hands and on the soles of the feet.
- Derma (middle layer): it is formed by connective tissue, soft and elastic. The dermis is crossed by capillaries, lymphatic vessels and nerve receptors (papillary layer). Furthermore, this portion allows the skin to remain elastic and tight, allowing adequate protection of the whole body (reticular layer).
- Hypoderm or subcutaneous (deeper layer): it connects the dermis and the epidermis to the internal tissues, allowing the anchorage on muscles and bones and favoring the adherence of the skin during the movement of the body.
What's this
Hyperkeratosis: what is it?
Hyperkeratosis is a disorder of keratinization in which an excessive increase in keratinocytes is observed, ie cells that constitute the most superficial part of the skin (stratum corneum).
Basically, skin alteration occurs as a response to an external insult, such as continuous and prolonged mechanical stress over time or rubbing phenomena on that specific skin portion. Plantar hyperkeratosis can occur, for example, in the form of calluses or calluses.
On other occasions, the disorder is the expression of pathological processes, such as inflammation, infections (such as papilloma virus infections) and genetic diseases . Furthermore, hyperkeratosis can be the result of chronic exposure to solar radiation .
Keratinocytes: short note
- Keratinocytes are the most superficial cells of the epidermis, whose name derives from the very stable and resistant filamentous protein they contain: keratin . This helps to make the outer layer of the skin resistant to rubbing, irritation and pressure.
- The keratinocytes are born from the germinative layer and gradually rise to the surface; during the journey, these elements undergo a degeneration that ends with terminal differentiation (that is, with the death of the cells) and peeling of the skin .
Causes
Hyperkeratosis is one of the most frequent keratinization abnormalities .
This can be conditioned by a genetic-familial predisposition or manifests itself in correlation to different disorders with skin involvement . Often, hyperkeratosis is the result of inflammation or chronic irritation, resulting from exposure to mechanical, infectious and toxic stimuli.
The forms of acquired hyperkeratosis, typical of the adult, can arise following local or general pathologies of various types (eg endocrine-metabolic, oncological, inflammatory, etc.) or of an unspecified nature.
Keratinization disorders: what are they?
The anomalies of the keratinization process are a group of skin diseases that involve the stratum corneum, that is the most superficial part of the skin.
For simplicity, these pathologies are classically divided into:
- Quantitative, like hyperkeratosis ;
- Qualitative, such as dyskeratosis and parakeratosis .
Hyperkeratosis is a condition in which there is a thickening of the stratum corneum of the epidermis. The areas affected by this process have very high amounts of keratin. In hyperkeratosis, the cells of the stratum corneum are devoid of nucleus, therefore in line with normal cytology.
Hyperkeratosis: what are the pathologies in which it manifests itself?
In dermatology, hyperkeratosis occurs in different forms, which include:
- Corns : they tend to develop in the parts of the body most exposed to rubbing or pressure, such as the sole of the foot and the palm of the hands. These stimuli lead to the formation of a thick layer of keratinized cells that cluster and solidify, giving rise to the characteristic protuberances. For some people, calluses represent simple imperfections, for others their presence is associated with annoyance and itching;
- Eczema : it is an inflammation of the skin, which can develop following irritation, exposure to chemical agents and allergic reactions. This condition can cause itching, redness and small blisters and is often confused with another inflammatory skin disease: psoriasis;
- Lichen planus : it is characterized by the appearance of small pustules inside the mouth and is often caused by a problem with the immune system;
- Warts : they are small skin growths caused by a papilloma virus (HPV) infection. This is transmitted by direct contact with people who already have a wart or through contaminated surfaces (eg walking barefoot in swimming pools or gyms);
- Seborrheic keratosis : these are benign (non-cancerous) growths that appear as marked growths of brownish skin and extremely different sizes (from one millimeter to a few centimeters). These papule-like lesions may appear on the face, arms or legs. The presence of these growths does not cause pain; however, if something irritates them, they could cause itching and be very annoying. The causes of this condition are still unknown, but a favorable genetic condition is thought to be highly predisposing;
- Keratosis pilare : also known as follicular keratosis, it is a fairly common disorder, characterized by an accumulation of keratin at the level of the orifices of the hair bulbs, in certain skin areas. The onset of keratosis pilare coincides with the appearance of point papules, similar to granules, generally rough and palpable to the touch, which tend spontaneously to resolution. Keratosis pilare can affect both children and adults. The cause is unknown, but a genetic implication has been hypothesized;
- Actinic keratosis : it is a benign precancerous disease that is characterized by the presence of one or more erythematous and rough scales on the skin, especially in the face, legs, arms, back of the hands and scalp. These lesions are often caused by excessive recurrent exposure to sunlight (chronic photoexposure) and can potentially turn into skin cancer. Sometimes, actinic keratosis is also responsible for itching and red-brownish lesions similar to warts.
The most peculiar forms of hyperkeratosis are:
- Epidermolytic hyperkeratosis (or epidermolytic ichthyosis) : it is a genetic disorder, fortunately very rare, characterized by a keratinocytic alteration of considerable gravity;
- Subungual hyperkeratosis : a variant that affects the nail bed or the cutaneous layer below the free edge of the nail. The causes determining this type of hyperkeratosis are diseases such as psoriasis or fungal infections. Failure to treat leads to permanent loss of the nail (onycholysis).
Leather, but not only
The hyperkeratosis can also be found in the gynecological field, therefore in the pathological conditions concerning the female genital apparatus . In this case, the pathogenesis is mainly determined by HPV infection and the transmission is sexual, so the infected person may present a hyperkeratosis at vulvar, vaginal and / or cervical level . For the same reason, hyperkeratotic cells can be observed in the oral cavity ( lingual or gingival hyperkeratosis ).
Symptoms
The hyperkeratosis causes a thickening that is manifested in formations more or less detected on the skin or on the mucous membranes.
This disorder can occur in all parts of the body, involving the entire skin (in this case, hyperkeratosis outlines a picture of ichthyosis) or selectively some areas, such as the palms of the hands or the soles of the feet (hyperkeratosis palm orthotics).
The increase in the thickness of the epidermis can be associated with a series of dermatological manifestations, such as itching and the appearance of scales. The most common forms of hyperkeratosis are not associated with pain.
Diagnosis
Hyperkeratosis should be appropriately evaluated by a doctor specialized in dermatology.
The diagnosis may imply:
- Collection of personal and family history data ;
- The objective examination of the area of the skin or of the mucous membranes involved, especially in correspondence with possible corns, warts and plaques;
In some cases, a biopsy may be required, then the removal of a small portion of tissue to be analyzed in the laboratory. This assessment allows defining or excluding whether hyperkeratosis is a consequence of inflammatory, tumor, degenerative or other processes.
Treatment
The treatment of hyperkeratosis may vary depending on the underlying disease, the area of the body involved and the severity of the condition. In general, the purpose is to soften the skin and remove keratin thickening.
Most forms of hyperkeratosis are located in specific areas of the body and correlate with a good prognosis. Actinic keratosis can give rise to skin cancer, so it requires more attention. In this case, the hyperkeratosis should be monitored at a rate established by the clinician (for example, every six to twelve months), so as to always keep the progression of the lesions under control.
How is hyperkeratosis treated?
In general, the strategies available to remedy the problem are based mainly on three action interventions:
- Topical drugs : it is a type of treatment that is chosen when the hyperkeratosis involves a limited area of the body. These medicines usually contain salicylic acid and urea and should be applied topically, in correspondence with cutaneous manifestations. Salicylic acid has a keratolytic function, capable of dissolving the horny layer of the epidermis and promoting exfoliation, making the skin softer and more hydrated.
- Systemic drugs : they are administered based on the extent of the disease; the use of these medicines is indicated when the hyperkeratosis and the manifestations associated with it are widespread and simultaneously concern more districts of the body;
- Phototherapy : artificial sources of UVA and UVB rays are used, specifically calibrated for the individual case.
In the presence of calluses and warts, other therapies are generally recommended. For corns, just apply padding or protection to the affected area to reduce pain (eg orthopedic insoles), while warts can be eliminated by freezing them (for example, by cryotherapy, liquid nitrogen, etc.) or by treating them with a laser . In any case, it is advisable to strictly follow the indications provided by the dermatologist or your primary care physician.
