It is commonly misdiagnosed as chickenpox or rosacea. Pleva is also often misidentified as a form of staph. The most accurate way to diagnose it is by biopsy. This disease has not been known to be life-threatening. However, there may be mutations of the disease that can cause ulcers on the exterior.

The dry scaling appearance is most noticeable during the winter as a result of dry air inside people's homes. During the summer, tanning of the surrounding normal skin makes the pale patches of pityriasis alba more prominent.

Individual lesions develop through 3 stages and sometimes are itchy:

1. Raised and red – although the redness is often mild and not noticed by parents

2. Raised and pale

3. Smooth flat pale patches

Lesions are round or oval raised or flat, of 0.5–2 cm in size although may be larger if they occur on the body (up to 4 cm), and usually number from 4 or 5 to over 20. The patches are dry with very fine scales. They most commonly occur on the face (cheeks), but in 20% appear also on the upper arms, neck, or shoulders.

The diagnostic differential should consider tinea and vitiligo amongst other causative factors.

Pityriasis lichenoides et varioliformis acuta is a disease of the immune system. It is the more severe version of pityriasis lichenoides chronica. The disease is characterized by rashes and small lesions on the skin. The disease is more common in males and usually occurs in young adulthood, although it has been seen in every age group and every race. It is possible for the disease to go into remission for short periods of time or forever.

Pityriasis rubra pilaris (also known as "Devergie's disease," "Lichen ruber acuminatus," and "Lichen ruber pilaris") refers to a group of chronic disorders characterized by reddish orange, scaling plaques and keratotic follicular papules. Symptoms may include reddish-orange patches (Latin: "rubra") on the skin, severe flaking (Latin: "pityriasis"), uncomfortable itching, thickening of the skin on the feet and hands, and thickened bumps around hair follicles (Latin: "pilus" for hair). For some, early symptoms may also include generalized swelling of the legs, feet and other parts of the body. PRP has a varied clinical progression and a varied rate of improvement. There is no known cause or cure although stress is a common factor.

It was first described by Marie-Guillaume-Alphonse Devergie in 1856, and the condition is also known as Devergie's disease.

The symptoms of this condition include:

- An upper respiratory tract infection may precede all other symptoms in as many as 69% of patients.

- A single, 2- to (rarely) 10-cm oval red "herald" patch appears, classically on the abdomen. Occasionally, the "herald" patch may occur in a 'hidden' position (in the armpit, for example) and not be noticed immediately. The "herald" patch may also appear as a cluster of smaller oval spots, and be mistaken for acne. Rarely, it does not become present at all.

- 7–14 days after the herald patch, many small (5–10 mm) patches of pink or red, flaky, oval-shaped rash appear on the torso. The more numerous oval patches generally spread widely across the chest first, following the rib-line in a characteristic "christmas-tree" distribution. Small, circular patches may appear on the back and neck several days later.

- In 6% of cases an "inverse" distribution may occur, with rash mostly on the extremities. In children, presentation can be atypical or inverse, and the course is typically milder.

- About one in four people with PR have mild to severe symptomatic itching. (Moderate itching due to skin over-dryness is much more common, especially if soap is used to cleanse the affected areas.) The itching is often non-specific, and worsens if scratched. This tends to fade as the rash develops and does not usually last through the entire course of the disease.

- The rash may be accompanied by low-grade fever, headache, nausea and fatigue.

Although other forms of the disease occur at younger ages, some individuals start having long term symptoms at thirty years of age. This disease also affects adolescents and young adults. This also affects the immune system which therefore results in rashes. The symptoms rarely affect the face or scalp, but occurs at other sites of the body. The duration may last for months or even several years. For instance, new crops of lesions appear every few weeks.

Dr. W.A.D. Griffiths, from Great Britain, classified six forms of PRP in the early 1980s. At this time, the causes of PRP are still unknown and symptoms can be difficult to diagnose. Frequently, more than one medical professional will be consulted before an accurate PRP diagnosis is made.

Dermatologists have identified both an acquired form and an inherited form (familial) of PRP and have described them in medical journals. The acquired form usually shows a spontaneous or gradual remission of symptoms within several years although long-term symptoms may continue for years. The inherited form starts early in childhood with persistent long-term symptoms into adulthood.

Although most people who develop PRP are over age 50, individuals of any age, race, and nationality can be affected. Women and men seem to be equally affected.

Clinical diagnostic features are lifelong eruptions of pityriasis versicolor-like macules, flat wart-like papules, one to many cutaneous horn-like lesions, and development of cutaneous carcinomas.

Patients present with flat, slightly scaly, red-brown macules on the face, neck, and body, recurring especially around the penial area, or verruca-like papillomatous lesions, seborrheic keratosis-like lesions, and pinkish-red plane papules on the hands, upper and lower extremities, and face. The initial form of EV presents with only flat, wart-like lesions over the body, whereas the malignant form shows a higher rate of polymorphic skin lesions and development of multiple cutaneous tumors.

Generally, cutaneous lesions are spread over the body, but some cases have only a few lesions which are limited to one extremity.

Pityriasis alba is a common skin condition mostly occurring in children and usually seen as dry, fine-scaled, pale patches on the face. It is self-limiting and usually only requires use of moisturizer creams.

The condition is so named for the fine scaly appearance initially present (pityriasis) and the pallor of the patches that develop (while "alba" is Latin for white, the patches in this condition are not totally depigmented).

Occurring at any age these lesions appear as raised pink-red ring or bulls-eye marks. They range in size from . The lesions sometimes increase size and spread over time and may not be complete rings but irregular shapes. Distribution is usually on the thighs and legs but can also appear on the upper extremities, areas not exposed to sunlight, trunk or face. Currently EAC is not known to be contagious, but as many cases are incorrectly diagnosed as EAC, it is difficult to be certain.

Lichen striatus is defined by:

The papules could be smooth, flat topped or scaly. The band of lichen striatus varies from a few millimeters to 1-- 2 cm wide and extends from a few centimeters to the complete length of the extremity. By and big, the papules are unilateral and single on an extremity along the lines of Blaschko.

Pityriasis lichenoides is a form of pityriasis.

Types include:

- Pityriasis lichenoides et varioliformis acuta

- Pityriasis lichenoides chronica

Parapsoriasis refers to one of a group of skin disorders that are characterized primarily by their resemblance to psoriasis (red, scaly lesions), rather than by their underlying cause.

Neoplasms can develop from parapsoriasis. For example, it can develop into cutaneous T-cell lymphoma.

The word "parapsoriasis" was formed in 1902.

Although lichen planus can present with a variety of lesions, the most common presentation is as a well defined area of purple-coloured, itchy, flat-topped papules with interspersed lacy white lines (Wickham's striae). This description is known as the characteristic "6 Ps" of lichen planus: planar (flat-topped), purple, polygonal, pruritic, papules, and plaques. This rash, after regressing, is likely to leave an area of hyperpigmentation that slowly fades. That said, a variety of other lesions can also occur.

Types include:

- Pityriasis alba

- Pityriasis lichenoides chronica

- Pityriasis lichenoides et varioliformis acuta

- Pityriasis rosea

- Pityriasis circinata

- Pityriasis rubra pilaris

- Pityriasis versicolor

- Dandruff, historically called "Pityriasis capitis"

- Pityriasis amiantacea

Pityriasis rotunda (also known as "Pityriasis circinata" and "Tinea circinata") is a disorder of keratisation of the skin that manifests as a perfectly circular, scaly patches on the torso and proximal portions of the extremities. It may be associated with diseases like hepatocellular carcinoma in racially predisposed groups.

The parapsoriasis groups, described and debated for nearly a century, has spawned a confusing nomenclature. There are some authors who prefer to limit the term "parapsoriasis" to large- and small-plaque variants only. However, the following classification scheme is now generally accepted:

- Large-plaque parapsoriasis

- Small-plaque parapsoriasis

- Pityriasis lichenoides

- Pityriasis lichenoides chronica

- Pityriasis lichenoides et varioliformis acuta

- Lymphomatoid papulosis

Gougerot–Blum syndrome (also known as "pigmented purpuric lichenoid dermatitis", and "pigmented purpuric lichenoid dermatitis of Gougerot and Blum") is a variant of pigmented purpuric dermatitis, a skin condition characterized by minute, rust-colored to violaceous, lichenoid papules that tend to fuse into plaques of various hues. Relative to other variants, it is characterized clinically by a male predominance, pruritus, with a predilection for the legs, and histologically, it features a densely cellular lichenoid infiltrate.

It was characterized in 1925.

Gougerot–Blum syndrome is named after the French dermatologists Henri Gougerot (1881–1955) and Paul Blum (1878–1933).

Onychauxis presents with thickened nails without deformity, and this simple thickening may be the result of trauma, acromegaly, Darier's disease, psoriasis, or pityriasis rubra pilaris, or, in some cases, hereditary.

Variants of cutaneous lichen planus are distinguished based upon the appearance of the lesions and/or their distribution. Lesions can affect the:

- Extremities (face, dorsal hands, arms, and nape of neck). This is more common in Middle Eastern countries in spring and summer, where sunlight appears to have a precipitating effect.

- Palms and soles

- Intertriginous areas of the skin. This is also known as "Inverse lichen planus."

- Nails characterized by irregular longitudinal grooving and ridging of the nail plate, thinning of the nail plate, pterygium formation, shedding of the nail plate with atrophy of the nail bed, subungual keratosis, longitudinal erthronychia (red streaks), and subungual hyperpigmentation. A sand-papered appearance is present in around 10% of individuals with nail lichen planus.

- Hair and Scalp. The scalp is rarely affected by a condition known as lichen planopilaris, acuminatus, follicular lichen planus, and peripilaris, characterised by violaceous, adherent follicular scale with progressive scarring alopecia. While lichen planus and lichen planopilaris may occur together, aside from sharing the term ‘lichen’ and revealing inflammation on skin biopsy, there is neither established data on their co-occurrence nor data to suggest a common etiology. Lichen planopilaris is considered an orphan disease with no definitive prevalence data and no proven effective treatments.

Other variants may include:

- "Lichen planus pemphigoides" characterized by the development of tense blisters atop lesions of lichen planus or the development vesicles de novo on uninvolved skin.

- "Keratosis lichenoides chronica" (also known as "Nekam's disease") is a rare dermatosis characterized by violaceous papular and nodular lesions, often arranged in a linear or reticulate pattern on the dorsal hands and feet, extremities, and buttock, and some cases manifest by sorrheic dermatitis-like eruption on the scalp and face; also palmo plantar keratosis has been reported.

- "Lichenoid keratoses" (also known as "Benign lichenoid keratosis," and "Solitary lichen planus") is a cutaneous condition characterized by brown to red scaling maculopapules, found on sun-exposed skin of extremities. Restated, this is a cutaneous condition usually characterized by a solitary dusky-red to violaceous papular skin lesion.

- "Lichenoid dermatitis" represents a wide range of cutaneous disorders characterized by lichen planus-like skin lesions.

Pityriasis lichenoides chronica is an uncommon, idiopathic, acquired dermatosis, characterized by evolving groups of erythematous, scaly papules that may persist for months.

Lichenoid trikeratosis is a cutaneous condition that may be related to keratosis lichenoides chronica.

Pityriasis rosea is a type of skin rash. Classically, it begins with a single red and slightly scaly area known as a "herald patch". This is then followed, days to weeks later, by a pink whole body rash. It typically lasts less than three months and goes away without treatment. Sometime a fever may occur before the start of the rash or itchiness may be present, but often there are few other symptoms.

While the cause is not entirely clear, it is believed to be related to human herpesvirus 6 (HHV6) or human herpesvirus 7 (HHV7). It does not appear to be contagious. Certain medications may result in a similar rash. Diagnosis is based on the symptoms.

Evidence for specific treatment is limited. About 1.3% of people are affected at some point in time. It most often occurs in those between the ages of 10 and 35. The condition was described at least as early as 1798.

Lichen scrofulosorum (also known as "Tuberculosis cutis lichenoides") is a rare tuberculid that presents as a lichenoid eruption of minute papules in children and adolescents with tuberculosis. The lesions are usually asymptomatic, closely grouped, skin-colored to reddish-brown papules, often perifollicular and are mainly found on the abdomen, chest, back, and proximal parts of the limbs. The eruption is usually associated with a strongly positive tuberculin reaction.

Of the three tuberculids, the incidence of lichen scrofulosorum was found to be the lowest (2%) in a large study conducted in Hong Kong. This highlights its rarity and significance as an important marker of undetected tuberculosis.

Pityriasis amiantacea (also known as "Tinea amiantacea") is an eczematous condition of the scalp in which thick tenaciously adherent scale infiltrates and surrounds the base of a group of scalp hairs. It does not result in scarring or alopecia.

Pityriasis amiantacea was first described by Alibert in 1832. Pityriasis amiantacea affects the scalp as shiny asbestos-like (amiantaceus) thick scales attached in layers to the hair shaft. The scales surround and bind down tufts of hair. The condition can be localised or covering over the entire scalp. Temporary alopecia and scarring alopecia may occur due to repeated removal of hairs attached to the scale. It is a rare disease with a female predilection.

Pityriasis amiantacea can easily be misdiagnosed due its close resemblance to other scalp diseases such as psoriasis, seborrhoeic dermatitis or lichen planus. However in pityriasis amiantacea the scales are attached to both the hair shaft and the scalp. Pityriasis amiantacea may be present with other inflammatory conditions such as atopic dermatitis or seborrhoeic dermatitis and sebaceous scales and alopecia can occur. According to the dermatology text Bolognia this condition is most often seen in psoriasis, but may also be seen in secondarily infected atopic dermatitis, seborrheic dermatitis, and tinea capitis.