The symptoms are equivalent to photodermatitis, but vary in severity.

The skin condition is a cutaneous phototoxic inflammatory eruption resulting from contact with light-sensitizing botanical substances—particularly from the plant families Umbelliferae, Rutaceae, Moraceae, and Leguminosae—and ultraviolet light, typically from sun exposure. Phytophotodermatitis usually results in hyperpigmentation of the skin that often appears like a bruise. This may be accompanied by blisters or burning. The reaction typically begins within 24 hours of exposure and peaks at 48–72 hours after the exposure.

Phytophotodermatitis can affect people of any age. Because of the bruise-like appearance that is usually in the shape of handprints or fingerprints, it can be mistaken in children for child abuse.

Phytophotodermatitis, also known as "lime disease" (not to be confused with "Lyme disease"), "Berloque dermatitis", or "Margarita photodermatitis" is a chemical reaction which makes skin hypersensitive to ultraviolet light. It is frequently mistaken for hereditary conditions such as atopic dermatitis or chemical burns, but it is caused by contact with the photosensitizing compounds—such as furanocoumarins—found naturally in some plants and vegetables like parsnips, citrus fruits and more. Symptoms include burning, itching and large blisters that slowly accumulate over time. One of the earliest descriptions of this disease was made by Darrell Wilkinson, a British dermatologist in the 1950s.

Riehl melanosis is a form of contact dermatitis, beginning with pruritus, erythema, and pigmentation that gradually spreads which, after reaching a certain extent, becomes stationary. The pathogenesis of Riehl melanosis is believed to be sun exposure following the use of some perfumes or creams (a photocontact dermatitis).

Scratch dermatitis (also known as "flagellate pigmentation from bleomycin") is a cutaneous condition characterized by linear hyperpigmented streaks are seen on the chest and back.

Fever and a non specific skin eruption – with reddening (erythema) and swelling (oedema) of the skin – are the most common symptoms of NEH. Patients usually present with the skin eruption 1-2 weeks after use of the cytotoxic drug. Sometimes, the skin eruption can be painful. Skin eruptions can be located on the extremities, trunk, and face. Severe lesions are rare, and can mimic cellulitis. Generalised lesions resembling erythema multiforme have been reported.

Erythema (from the Greek "erythros", meaning red) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not associated with pathology include nervous blushes.

It can be caused by infection, massage, electrical treatment, acne medication, allergies, exercise, solar radiation (sunburn), cutaneous radiation syndrome, mercury toxicity, blister agents, niacin administration, or waxing and tweezing of the hairs—any of which can cause the capillaries to dilate, resulting in redness. Erythema is a common side effect of radiotherapy treatment due to patient exposure to ionizing radiation.

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.

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.

Millipede burns are a cutaneous condition caused by some millipedes that secrete a toxic liquid that causes a brownish pigmentation or burn when it comes into contact with the skin. Some millipedes produce quinones in their defensive secretions, which have been reported to cause brown staining of the skin.

Shiitake mushroom dermatitis (also known as "flagellate mushroom dermatitis", "mushroom worker's disease", and "shiitake-induced toxicoderma") is an intensely pruritic dermatitis characterized by disseminated 1mm erythematous micropapules seen in a linear grouped arrangement secondary to Koebnerization due to patient scratching. It is caused by the ingestion of shiitake mushrooms and was first described in 1977 by Nakamura. Although it is rarely seen outside of China and Japan due to a lower incidence of shiitake consumption outside these regions, there is a well-established association between flagellate dermatitis and shiitake mushroom (Lentinula edodes) ingestion. Bleomycin ingestion may also cause similar findings. On physical exam, one key difference between the two is that post-inflammatory hyperpigmentation changes are usually seen with bleomycin-induced flagellate dermatitis and are not typically present with shiitake mushroom induced flagellate dermatitis. The median time of onset from ingestion of shiitake mushrooms is typically 24 hours, ranging from 12 hours to 5 days. Most patients completely recover by 3 weeks, with or without treatment. Although the pathogenesis of shiitake induced flagellate dermatitis is not clear, the theory most argued for is a toxic reaction to lentinan, a polysaccharide isolated from shiitake mushrooms. However, Type I and Type IV allergic hypersensitivities have also been supported by the 24-hour median time of onset, clearance in 3–21 days, severe pruritus, benefit of steroids and antihistamines, and lack of grouped outbreaks in people exposed to shared meals containing shiitake mushrooms. Most cases reported shortly after its discovery were due to consumption of raw shiitake mushrooms, but several cases have since been reported after consumption of fully cooked mushrooms.

Neutrophilic eccrine hidradenitis (NEH) usually is a cutaneous complication of chemotherapy, but it can also occur for other reasons. It consists of fever and non specific skin lesions. It is rare, and self-limited.

Drug-induced pigmentation of the skin may occur as a consequence of drug administration, and the mechanism may be postinflammatory hyperpigmentation in some cases, but frequently is related to actual deposition of the offending drug in the skin.The incidence of this change varies and depends on the type of medication involved. Some of the most common drugs involved are NSAIDs, Antimalarials, psychotropic drugs, Amiodarone, cytotoxic drugs, tetracyclines and heavy metals such as silver and gold (must be ingested not just worn).

The foremost symptoms of saree cancer are the constant irritation with scaling and pigmentation change at the waistline; gradually these become chronic. The person may have non-healing ulcer or a hyper- or hypopigmented patch or a growth-like lesion over the waistline. The lesion may be associated with serous discharge with foul smell.

Chrysiasis (Gk, "chrysos" – 'gold', "osis" – 'condition of') is a dermatological condition induced by the parenteral administration of gold salts, usually for the treatment of rheumatoid arthritis. Such treatment has been superseded as the best practice for treating the disease because of "numerous side effects and monitoring requirements, their limited efficacy, and very slow onset of action".

Similar to silver, a gold preparation used parenterally for a long period may rarely produce a permanent skin pigmentation – especially if the skin is exposed to sunlight or artificial ultraviolet radiation.

The skin's pigmentation (in this condition) has been described as uniformly gray, grayish purple, slate gray, or grayish blue, and is usually limited to exposed portions of the body. It may involve the conjunctivae over the scleras but usually not the oral mucosa. Location of pigment predominantly in the upper dermis leads to the blue component of skin color through the scattering phenomenon. It is much less likely to be deposited in the nails and hair.

Chrysiasis was said to have been much more common when medicines containing traces of gold were used for treatment of tuberculosis (commonplace forms of treatment nearly fifty years ago). Treatments containing gold traces were also used to treat cases of rheumatoid arthritis – but because the dose used for tuberculosis was higher than for arthritis, it has not afflicted many subscribing to such treatments.

Gold can be identified in the skin chemically by light microscopy, electron microscopy, and spectroscopy.

There is no way to reverse or treat chrysiasis.

Drug induced pigmentation may take on many different appearances, one of the most common being a change in the color, or pigmentation, of the skin.

Idiopathic eruptive macular pigmentation is a skin condition developing in young persons, with an average age of 11, characterized by asymptomatic widespread brown to gray macules of up to several centimeters in diameter on the neck, trunk, and proximal extremities.

Bismuthia is a rare dermatological condition that results from the prolonged use of bismuth.

Much more rarely than with silver, bismuth may produce a generalized persistent skin discoloration resembling argyria. This is known as bismuthia. The conjunctivae and oral mucosa, as well as skin, are commonly afflicted by the condition. Pigment granules are evenly scattered through the dermis, producing a blue, or bluish gray skin color by the scattering phenomenon. It is extremenly rare, and as a consequence is poorly understood by modern medicine. Special stains and spectroscopic methods must be utilized for identification of skin pigments affected by bismuth.

Usually, bismuth produces a black line, due to bismuth sulfide, along the gums, near the teeth, similar to a lead line. This is not likely to occur if the gum is edentulous or the gum and the teeth normal. It is more common when gingivitis and carious teeth are present. Bismuth excess may cause stomatitis. On even rarer occasions, bismuth has been reported to cause pigmentation of the vagina and cervix.

The saree is common female attire in the Indian subcontinent. It is a piece of long (generally ) cloth which can be made of various materials: cotton, silk, nylon, chiffon or synthetic fabric. It is worn over an inner skirt (petticoat) which is tightened around the waist by a thick cotton cord. This is the traditional costume of most Indian women. The saree is attached to the waist throughout the day in the hot and humid climate. The waist is often soiled with dust and sweat and remains without proper cleaning. This causes changes in pigmentation and mild scaling over the waist. This, in turn, causes chronic irritation and gradually malignancy may develop in the skin at the waistline.

Typical signs of acral lentiginous melanoma include the following

- Longitudinal tan, black, or brown streak on a finger

- Pigmentation of proximal nail fold

- Areas of dark pigmentation (on palms of hands)

Warning signs are new areas of pigmentation, or existing pigmentation that shows change. If caught early, acral lentiginous melanoma has a similar cure rate as the other types of superficial spreading melanoma.

Hyperpigmentation can be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris. People with darker skin tones are more prone to hyperpigmentation, especially with excess sun exposure.

Many forms of hyperpigmentation are caused by an excess production of melanin. Hyperpigmentation can be diffuse or focal, affecting such areas as the face and the back of the hands. Melanin is produced by melanocytes at the lower layer of the epidermis. Melanin is a class of pigment responsible for producing colour in the body in places such as the eyes, skin, and hair. As the body ages, melanocyte distribution becomes less diffuse and its regulation less controlled by the body. UV light stimulates melanocyte activity, and where concentration of the cells is greater, hyperpigmentation occurs. Another form of hyperpigmentation is post inflammatory hyperpigmentation. These are dark and discoloured spots that appear on the skin following acne that has healed.

Hyperpigmentation is associated with a number of diseases or conditions, including the following:

- Addison's disease and other sources of adrenal insufficiency, in which hormones that stimulate melanin synthesis, such as melanocyte-stimulating hormone (MSH), are frequently elevated.

- Cushing's disease or other excessive adrenocorticotropic hormone (ACTH) production, because MSH production is a byproduct of ACTH synthesis from proopiomelanocortin (POMC).

- Acanthosis nigricans—hyperpigmentation of intertriginous areas associated with insulin resistance.

- Melasma, also known as "chloasma"—patchy hyperpigmentation

- Acne scarring from post-inflammatary hyperpigmentation

- Linea nigra—a hyperpigmented line found on the abdomen during pregnancy.

- Peutz-Jeghers syndrome—an autosomal dominant disorder characterized by hyperpigmented macules on the lips and oral mucosa and gastrointestinal polyps.

- Exposure to certain chemicals such as salicylic acid, bleomycin, and cisplatin.

- Smoker's melanosis

- Coeliac disease

- Cronkite-Canada syndrome

- Porphyria

- Tinea fungal infections such as ringworm

- Haemochromatosis—a common but debilitating genetic disorder characterized by the chronic accumulation of iron in the body.

- Mercury poisoning—particularly cases of cutaneous exposure resulting from the topical application of mercurial ointments or skin-whitening creams.

- Aromatase deficiency

- Nelson's syndrome

- Grave's disease

- As a result of tinea cruris.

Hyperpigmentation can sometimes be induced by dermatological laser procedures.

Hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin.

Melanonychia is a black or brown pigmentation of the normal nail plate, and may be present as a normal finding on many digits in African-Americans, as a result of trauma, systemic disease, or medications, or as a postinflammatory event from such localized events as lichen planus or fixed drug eruption.

There are two types, longitudinal and transverse melanonychia. Longitudinal melanonychia may be a sign of subungual melanoma (acral lentiginous melanoma), although there are other diagnoses such as chronic paronychia, onychomycosis, subungual hematoma, pyogenic granuloma, glomus tumour, subungual verruca, mucous cyst, subungual fibroma, keratoacanthoma, carcinoma of the nail bed, and subungual exostosis.

Hemosiderin hyperpigmentation is pigmentation due to deposits of hemosiderin, and occurs in purpura, hemochromotosis, hemorrhagic diseases, and stasis dermatitis.

Amalgam tattoo (also termed localized argyrosis, or focal argyrosis) is a grey, blue or black area of discoloration on the mucous membranes of the mouth, typically on the gums of the lower jaw. It is an iatrogenic lesion, caused by entry of dental amalgam into the soft tissues. It is common, painless, and benign, but it can be mistaken for melanoma.