The lesions are most frequent on the lower limbs, but may occur anywhere on the body, including the hands, arms, torso and even the neck. They may vary in number and erupt in mass numbers.

They consist of irregular patches of orange or brown pigmentation with characteristic "cayenne pepper" spots appearing within and at the edge of old lesions.

There are usually no symptoms, although there may be some slight itching, but there is no pain.

The eruption may persist for many years. The pattern of the eruption changes, with slow extension and often some clearing of the original lesions.

Schamberg's disease, or progressive pigmented purpuric dermatitis, is a chronic discoloration of the skin which usually affects the legs and often spreads slowly. This disease is more common in males and may occur at any age from childhood onward. This condition is observed worldwide and has nothing to do with race or ethnic background.

PVA can be characterized by speckled, combined hyper- and hypopigmentation in the plaques or patches of affected skin. Hyperpigmentation is excess coloration, or darkening of the skin, while hypopigmentation is a diminished or pallid coloring to the skin. Pigmentation changes in PVA, apparent in the epidermal (outermost) skin layer, may be attributed to incontinence (leaking out) of melanin from melanocytes into the dermal skin layer below. Inflammation of the skin and cutaneous tissue, common with PVA, also contributes to color changes in the skin, typified by redness. Telangiectasia, the visible "vascular" element of PVA, is the of small blood vessels near the skin surface. Skin atrophy, a wasting-away of the tissue comprising the skin, is a prominent part of PVA and effects the dermal, and particularly the epidermal layer. This, in part, is the result of degenerative of the stratum basale (bottom cell-layer) of the epidermis. Atrophy of the skin gives it a thin, dry and wrinkled appearance, which in PVA-affected individuals has been described as "cigarette paper". Hyperkeratosis, a thickening of the stratum corneum (top cell-layer of the epidermis), has also been reported.

The symptoms of this condition include:

- Occasional fine scaling of the skin producing a very superficial ash-like scale

- Pale, dark tan, or pink in color, with a reddish undertone that can darken when the patient is overheated, such as in a hot shower or during/after exercise. Tanning typically makes the affected areas contrast more starkly with the surrounding skin.

- Sharp border

Pityriasis versicolor is more common in hot, humid climates or in those who sweat heavily, so it may recur each summer.

The yeasts can often be seen under the microscope within the lesions and typically have a so-called "spaghetti and meatball appearance" as the round yeasts produce filaments.

In people with dark skin tones, pigmentary changes such as hypopigmentation (loss of color) are common, while in those with lighter skin color, hyperpigmentation (increase in skin color) is more common. These discolorations have led to the term "sun fungus".

"Distribution" refers to how lesions are localized. They may be confined to a single area (a patch) or may exist in several places. Some distributions correlate with the means by which a given area becomes affected. For example, contact dermatitis correlates with locations where allergen has elicited an allergic immune response. Varicella zoster virus is known to recur (after its initial presentation as chicken pox) as herpes zoster ("shingles"). Chicken pox appears nearly everywhere on the body, but herpes zoster tends to follow one or two dermatomes; for example, the eruptions may appear along the bra line, on either or both sides of the patient.

- Generalized

- Symmetric: one side mirrors the other

- Flexural: on the front of the fingers

- Extensor: on the back of the fingers

- Intertriginous: in an area where two skin areas may touch or rub together

- Morbilliform: resembling measles

- Palmoplantar: on the palm of the hand or bottom of the foot

- Periorificial: around an orifice such as the mouth

- Periungual/subungual: around or under a fingernail or toenail

- Blaschkoid: following the path of Blaschko's lines in the skin

- Photodistributed: in places where sunlight reaches

- Zosteriform or dermatomal: associated with a particular nerve

IBS has symptoms very similar to epidermolytic hyperkeratosis (EHK) but is generally milder than EHK. IBS affects only the upper layers of the epidermis whilst EHK affects the suprabasal layer which is deeper in the

skin.

At birth the baby's skin has a red appearance like a sun burn (erythema). Blistering is usually present at birth and may be extensive or localized depending on the severity of the disease.

Over the first few weeks the redness disappears and is replaced by dry, flaking skin on the arms, legs and around the belly button. Other areas of skin appear normal. The skin is fragile and is prone to blistering (caused by mild trauma or sweating). After a few months hyperkeratosis develops with a dark grey or brown, ridged appearance on the ankles, knees and elbows. Palms and soles are generally unaffected. A slightly unpleasant, sweet odour may be present.

A distinctive characteristic of IBS which is not present in other forms of ichthyosis is called the "Mauserung phenomenon" (Mauserung is German for "moulting" and was first described by H.W.Siemens). These are small patches of bare, apparently normal skin in the middle of areas of hyperkeratosis.

As the sufferer ages the flaking and blistering should improve. The hyperkeratosis may grow more severe but more localized and is generally only present on flexural folds of the major joints.

"Configuration" refers to how lesions are locally grouped ("organized"), which contrasts with how they are distributed (see next section).

- Agminate: in clusters

- Annular or circinate: ring-shaped

- Arciform or arcuate: arc-shaped

- Digitate: with finger-like projections

- Discoid or nummular: round or disc-shaped

- Figurate: with a particular shape

- Guttate: resembling drops

- Gyrate: coiled or spiral-shaped

- Herpetiform: resembling herpes

- Linear

- Mammillated: with rounded, breast-like projections

- Reticular or reticulated: resembling a net

- Serpiginous: with a wavy border

- Stellate: star-shaped

- Targetoid: resembling a bullseye

- Verrucous: wart-like

There are also a number of medical conditions that cause blisters. The most common are chickenpox, herpes, impetigo, and a form of eczema called dyshidrosis. Other, much rarer conditions that cause blisters include:

- Bullous pemphigoid: a skin disease that causes large, tightly filled blisters to develop, usually affecting people over the age of 60.

- Pemphigus: a serious skin disease in which blisters develop if pressure is applied to the skin; the blisters burst easily, leaving raw areas that can become infected.

- Dermatitis herpetiformis: a skin disease that causes intensely itchy blisters, usually on the elbows, knees, back and buttocks. The blisters usually develop in patches of the same shape and size on both sides of the body.

- Chronic bullous dermatosis: a disease that causes clusters of blisters on the face, mouth or genitals.

- Cutaneous radiation syndrome

- Epidermolysis bullosa

The symptoms of the inherited form of ichthyosis vulgaris are not usually present at birth but generally develop between 3 months and 5 years of age. The symptoms will often improve with age, although they may grow more severe again in old age.

The condition is not life-threatening; the impact on the patient, if it is a mild case, is generally restricted to mild itching and the social impact of having skin with an unusual appearance. People afflicted with mild cases have symptoms that include scaly patches on the shins, fine white scales on the forearms and upper arms, and rough palms. People with the mildest cases have no symptoms other than faint, tell-tale "mosaic lines" between the Achilles tendons and the calf muscles.

Severe cases, although rare, do exist. Severe cases entail the buildup of scales everywhere, with areas of the body that have a concentration of sweat glands being least affected. Areas where the skin rubs against each other, such as the armpits, the groin, and the "folded" areas of the elbow and knees, are less affected. When the buildup of scales is bad, the person with a severe case suffers from "prickly itch" when he or she needs to sweat but cannot because of the scales. Various topical treatments are available to "exfoliate" the scales. These include lotions that contain alpha-hydroxy acids.

Intense rubbing can cause a blister, as can any friction on the skin if continued long enough. This kind of blister is most common after walking long distances or by wearing old or poorly fitting shoes. Blisters are most common on the hands and feet, as these extremities are susceptible while walking, running, or performing repetitive motions, such as joystick manipulation whilst playing certain video games, digging with a shovel, playing guitar, etc. Blisters form more easily on moist skin than on dry or soaked skin, and are more common in warm conditions. Less-aggressive rubbing over long periods of time may cause calluses to form rather than a blister. Both blisters and calluses can lead to more serious complications, such as foot ulceration and infection, particularly when sensation or circulation is impaired, as in the case of diabetes, neuropathy or peripheral artery disease (PAD).

Poikiloderma vasculare atrophicans, or PVA, indicates that extra or altered skin pigmentation ("poikiloderma") is occurring, associated with heightened visibity of capillaries ("", referring to telangiectasia) under the skin, related to thinning and wasting away ("") of the skin and its tissue. Telangiectasia is an enlargement of capillaries underneath the skin.

PVA also has common names that include parapsoriasis-related terminology (i.e. parapsoriasis variagata, or "" parapsoriasis). Parapsoriasis is a term first used by Brocq in 1902, intended to represent a group comprising a number of uncommon skin disorders, under a once used, now antiquated classification scheme for all inflammatory dermatoses (skin diseases known to be associated with or cause inflammation). Brocq chose the term "parapsoriasis" to illustrate that the dermatoses placed in this group had or would have commonalities with psoriasiasis, including appearance and chronicity (lifelong or indefinite duration). This poorly designated grouping has led to confusion in establishing a nosology (a method of classifying diseases and disorders) that associated or distinguished these disorders, and through the years differing opinions and uses regarding parapsoriasis by both authors and physicians has caused further confusion. In more recent times, after much discussion and growing consensus, parapsoriasis and its terminology has been revisited and re-examined often. Newer thought on parapsoriasis, such as by Sutton (1956) all the way to that by Sehgal, "et al." (2007) has cleared much of the confusion and has sparked increased understanding of parapsoriasis and its constituents.

PVA fits within this updated view of parapsoriasis as a syndrome often associated with large plaque parapsoriasis and, or including its variant form, retiform parapsoriasis. Additionally, it may be considered a precursor or variant of the lymphomatous skin disorder mycosis fungoides, which is also associated with large plaque parapsoriasis. Large plaque parapsoriasis consists of inflamed, oddly discolored (such as yellow or blue), web-patterned and scaling plaques on the skin, or larger in diameter. When the condition of the skin encompassed by these plaques worsens and becomes atrophic, it is typically considered retiform parapsoriasis. PVA can occur in either the large plaque or retiform stage, but it can only be considered PVA when its three constituents (poikiloderma, telangiectasia, atrophy) are present. PVA is therefore considered an independent syndrome identified by its constituents, wherever it occurs.

In modern consideration and usage, the solitary term "poikiloderma" has also come to represent all three elements of PVA. When skin diseases and disorders or skin conditions described as dermatoses contain the term poikiloderma in their assessment or diagnosis (such as with Bloom syndrome), this can sometimes be an erroneous usage of the term. Discretion has been advised. Usage of the entire term "poikiloderma vasculare atrophicans" may also be reserved to indicate it as the primary condition affecting the skin in cases where the disorder associated with it is secondary.

Many people with severe ichthyosis have problems sweating due to the buildup of scales on the skin. This may lead to problems such as "prickly itch" or problems associated with overheating. The majority of people with vulgaris can sweat at least a little. Paradoxically this means most would be more comfortable living in a hot and humid climate. Sweating helps to shed scales which improves the appearance of the skin and prevents "prickly itch".

The dry skin will crack on digits or extremities and create bloody cuts. Skin is painful when inflamed and/or tight.

For children and adolescents: psychological precautions may include inconsistent self-image, mood fluctuates due to cyclical outbreaks, prone to addiction, may socially withdraw and/or separate when skin is noticeably infected, pre-occupation with appearance.

Strong air-conditioning and excessive consumption of alcohol can also increase the buildup of scales.

Over 50% of people with ichthyosis vulgaris suffer from some type of atopic disease such as allergies, eczema, or asthma. Another common condition associated with ichthyosis vulgaris is keratosis pilaris (small bumps mainly appearing on the back of the upper arms).

A lack of sleep can cause paleness of the skin, allowing the blood underneath the skin to become more visible and appear more blue or darker.

Xeroderma or xerodermia (also known as xerosis cutis), derived from the Greek words for "dry skin", is a condition involving the integumentary system, which in most cases can safely be treated with emollients or moisturizers. Xeroderma occurs most commonly on the scalp, lower legs, arms, hands, the knuckles, the sides of the abdomen, and thighs. Symptoms most associated with xeroderma are scaling (the visible peeling of the outer skin layer), itching, and skin cracking.

Sufferers experience very fragile skin, with blisters and skin erosion occurring in response to relatively benign trauma. Blisters may form all over the body, including the mucous membranes. Chronic scarring can lead to the formation of granulation tissue, which may bleed easily, predisposing to infection. Hands and fingers may be affected, as well as various joints.

Any condition that causes the eyes to itch can contribute to darker circles due to rubbing or scratching the skin around them. Hay fever sufferers in particular will notice under-eye "smudges" during the height of the allergy season.

Schamberg's disease, (also known as "progressive pigmentary dermatosis of Schamberg", "purpura pigmentosa progressiva" (PPP), and "Schamberg's purpura") is a chronic discoloration of the skin found in people of all ages, usually affecting the legs. It slowly spreads throughout the body, and is most common in males. It is named after Jay Frank Schamberg, who described it in 1901. There is no known cure for this disease and it is not a life-threatening condition. The skin lesions may cause itching, which can be treated by applying cortisone cream. The cortisone cream will only help with the itching and the discoloration of the skin will remain, which may cause a cosmetic concern in the future. Schamberg's disease is usually asymptomatic meaning that it shows no signs of this condition, except for the discoloration of the skin. This condition is caused by leaky blood vessels, where red blood cells escape near the surface of skin and release its iron into the surrounding tissue. The cause of the leaky capillaries is unknown.

Epidermolytic hyperkeratosis is a skin disorder that is present at birth. Affected babies may have very red skin (erythroderma) and severe blisters. Because newborns with this disorder are missing the protection provided by normal skin, they are at risk of becoming dehydrated and developing infections in the skin or throughout the body (sepsis).

As affected individuals get older, blistering is less frequent, erythroderma becomes less evident, and the skin becomes thick (hyperkeratotic), especially over joints, on areas of skin that come into contact with each other, or on the scalp or neck. This thickened skin is usually darker than normal. Bacteria can grow in the thick skin, often causing a distinct odor.

Epidermolytic hyperkeratosis can be categorized into two types. People with PS-type epidermolytic hyperkeratosis have thick skin on the palms of their hands and soles of their feet (palmoplantar or palm/sole hyperkeratosis) in addition to other areas of the body. People with the other type, NPS-type, do not have extensive palmoplantar hyperkeratosis but do have hyperkeratosis on other areas of the body.

Epidermolytic hyperkeratosis is part of a group of conditions called ichthyoses, which refers to the scaly skin seen in individuals with related disorders. However, in epidermolytic hyperkeratosis, the skin is thick but not scaly as in some of the other conditions in the group.

"http://ghr.nlm.nih.gov/condition/epidermolytic-hyperkeratosis"

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.

The condition pityriasis versicolor was first identified in 1846. Versicolor comes from the Latin, from "" to turn + color. It is also commonly referred to as Peter Elam's disease in many parts of South Asia.

This benign patch appears on the skin at birth or in early childhood. In most people these are under 10cm in size. If there is doubt about the diagnosis, rubbing the area causes the skin around the lesion to become red while the lesion itself does not change in color. Often the patches are difficult to see against the background color of the patient’s skin, but if sunburn develops, then the white area stands out prominently. The involved area is lighter than the normal skin, not because of a loss of pigment occurs, but because blood vessels are constricted, producing a permanent blanching of the area. This blanching is a functional rather than a structural abnormality, presumed to be caused by local increased sensitivity to catecholamines. Although the cutaneous vasculature appears normal histologically, the blood vessels within the nevus do not respond to injection of vasodilators. It has been postulated that the persistent pallor may represent a sustained localized adrenergic vasoconstriction. Results of a skin biopsy would be interpreted as normal and only physiological testing can reveal the nevus in contrast to normal skin. Stroking the patch elicits no red flare. Only the normal skin would react with a characteristic erythematous response. Examination under a Wood lamp can also reveal the nevus anemicus patch will not emphasize as a patch of vitiligo would.

It begins as painless reddish-brown nodules which slowly enlarge to form irregularly shaped red plaque.

Nevus anemicus is a congenital disorder characterized by macules of varying size and shape that are paler than the surrounding skin and cannot be made red by trauma, cold, or heat. The paler area is due to the blood vessels within the area which are more sensitive to the body’s normal vasoconstricting chemicals.

Maceration is defined as the softening and breaking down of skin resulting from prolonged exposure to moisture. It was first described by Jean-Martin Charcot in 1877. Maceration is caused by excessive amounts of fluid remaining in contact with the skin or the surface of a wound for extended periods.

Maceration often occurs when one applies a bandage to everything from a paper cut on the finger to much larger wounds that require professional treatment. One may also notice maceration after wearing non-breathable plastic or latex rubber gloves, which trap moisture against the skin.

Maceration also occurs during treatment of wounds because the skin under the bandage becomes wet due to perspiration, urine or other bodily fluids. The excess moisture is sometimes called hyperhydration.

Wrinkles are the first sign that the skin is over-hydrated. In addition, macerated skin becomes extremely soft and takes on a whitish appearance. However, this white skin should not be confused with the pale, whitish appearance of the new epithelial tissue in a healing wound.

Although most maceration clears up quickly once the skin is exposed to fresh air and allowed to dry, sometimes skin that experiences long periods of maceration is vulnerable to fungal and bacterial infection. As opportunistic organisms affect the area, it may become itchy or develop a foul odour.

Keratosis pilaris results in small bumps on the skin that feel like rough sandpaper. They are skin-colored bumps the size of a grain of sand, many of which are surrounded by a slight pink color in light skinned people and dark spots in dark skinned people. Most people with keratosis pilaris do not have symptoms but the bumps in the skin can occasionally be itchy.

Though people with keratosis pilaris experience the condition year-round, the problem can become exacerbated and the bumps are likely to look and feel more pronounced in color and texture during the colder months when moisture levels in the air are lower. The symptoms may also worsen during pregnancy or after childbirth.

Their color is typically similar to that of the skin. Small black dots may occur on the surface. One or more may occur in an area. They may result in pain with pressure such that walking may be difficult.

Xeroderma is a very common condition. It happens more often in the winter when the cold air outside and the hot air inside creates a low relative humidity. This causes the skin to lose moisture and it may crack and peel. Bathing or hand washing too frequently, especially if one is using harsh soaps, can contribute to xeroderma. Xeroderma can be caused by a deficiency of vitamin A, vitamin D, systemic illness, severe sunburn, or some medication. Xeroderma can be caused by choline inhibitors. Detergents such as washing powder and dishwashing liquid can cause xeroderma.