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Dermatology Library

P

PABA:

Short for para-aminobenzoic acid. It is used in many sunscreens. It works well, but some people are allergic to it. If you're allergic to PABA, use a PABA-free sunscreen instead.

Palmoplantar Keratoderma:

Palmoplantar keratoderma Palmoplantar keratoderma or keratosis palmaris et plantaris is part of a group of disorders of the skin, where thickening of the palms and soles occurs. The condition may be hereditary, acquired, or part of another disease with PPK as an associated feature. Treatment of all types of hereditary and nonhereditary keratodermas is difficult. The most common therapeutic options result in short-term improvement and are frequently compounded by unacceptable adverse effects. Treatment tends to be symptomatic and may vary from simple measures (eg, saltwater soaks, paring) to topical keratolytics, systemic retinoids. Careful selection of footwear and treatment of fungal infections are important. Dermabrasion may permit increased penetration of topical agents, and carbon dioxide laser treatment may be beneficial in persons with limited keratodermas. For severe keratoderma, surgery may be considered. Total excision of hyperkeratotic skin followed by grafting has been successful in a number of cases. Palmoplantar keratoderma

Submitted by: Mickelle Riley, MSN, ARNP, NP-C

Papillomavirus (Human Papillomavirus):

See: Warts

Papules:

Pink bumps on the skin.

Parapsoriasis:

Parapsoriasis Definition - Parapsoriasis describes a group of skin diseases that are characterized by scaly patches or slightly elevated plaques that resemble psoriasis.

Description

  • Parapsoriasis refers to tow disease processes that are caused by T-cell infiltrates in the skin.
  • Concern results from whether the condition will progress to cutaneous T-cell lymphoma.
  • Two forms have emerged—small plaque parapsoriasis and large plaque parapsoriasis.
  • Small plaque parapsoriasis is a benign disorder that rarely progresses to cutaneous T-cell.
  • Large plaque parapsoriasis is more ominous in that 10% of patients will progress to cutaneous T-cell lymphoma. This disorder manifests in an indolent manner and progresses over many years. It is chronic and treatment is recommended because it may prevent progression. It does not enter remission without treatment.

Causes

  • The initiating cause is unknown, but the diseases likely represent different stages in a continuum of lymphoproliferative disorders ranging from chronic dermatitis to malignancy.
  • No specific association has been made with contact exposure or infection.
  • Two forms have emerged—small plaque parapsoriasis and large plaque parapsoriasis.

Diagnosis

  • Diagnosis is made through multiple biopsies and blood work.
  • Because of the nature of the disorder, biopsies may be required over a period of months.

Parapsoriasis Treatment

  • Small plaque parapsoriasis is treated by alleviating symptoms associated with scaliness. Topical steroids are frequently recommended.
  • Large plaque parapsoriases is treated using topical steroids.
  • Regular follow up is recommended to monitor increases in number of lesions and size of lesions. Any increase may result in repeat biopsies.

Submitted by: Elisa D. Endicott, P.A.-C.

Pediculosis:

See: Head Lice

Pemphigus vulgaris:

Pemphigus vulgaris (PV) is one of a group of chronic, relapsing auto-immune diseases causing blistering of the skin and mucosal membranes. Substances called antibodies produced by the immune system normally attack hostile viruses and bacteria. In a person with pemphigus, the immune system mistakenly regards the cells in skin and mucous membranes as foreign, and attacks them. This causes burn-like lesions or blisters that do not heal. Pemphigus vulgaris is very rare. There is no cure but it is controllable with heavy immunosuppressive treatment. It is non-infectious.

Perioral Dermatitis:

Description

  • Perioral dermatitis is best described as papules and pustules on a red and sometimes scaly base. Occurs around the mouth and nose.
  • Can sometimes resemble acne.
  • Occurs mostly in women ages 20-50.
  • May experience some itching, burning, or feelings of tightness in face.

Causes

  • Steroid use on the face.
  • Tarter control toothpaste.
  • Cinnamon gum.
  • Over use of moisturizing creams.

Diagnosis - Can be made by visualization of eruption and history from patient.

Treatment

  • Discontinuation of all topical steroids will cause condition to flare but is necessary to resolve the condition.
  • It may be treated with oral antibiotics, topical antibiotic, and topical non steroidal creams.
  • Avoid other possible triggers such as cinnamon, tater control toothpaste, ect..

Submitted by: Heather R. Brock, MSN, ARNP, NP-C

Phlebectomy:

A treatment for varicose veins. The enlarged vein is removed through tiny incisions made along its length. The procedure is called ambulatory phlebectomy when it is performed in an outpatient facility and the patient goes home the same day.

Also see: Veins

Photoaging/Photodamage:

Photodamage may be chronic or acute; acute photodamage is a sunburn. Photoaging and photodamage (dermatoheliosis) are terms used interchangeably to describe those chronic changes in the appearance and function of the skin caused by repeated sun exposure rather than by the passage of time (the latter called intrinsic or chronologic aging). Overwhelming epidemiologic and laboratory evidence indicates that sun exposure and other sources of UV radiation (UVR) play the major role in causing the undesirable skin changes of fine and coarse wrinkles, roughness, laxity, mottled pigmentation, actinic lentigines, actinic keratoses, leathery texture/coarseness, scaling/xerosis, sallowness, and telangiectasia. Cigarette smoking is the only other environmental factor that has been related to the development of changes in the skin associated with aging. Because there is equally compelling evidence that UVR, from sun exposure or artificial sources, or both, is associated with an increased incidence of benign, premalignant, and malignant skin neoplasms, the changes of photoaging/photodamage have important epidemiologic significance, as well as aesthetic implications and are therefore not trivial concerns. No credible scientific evidence contradicts the relation of sun exposure to the development of skin cancer and the undesirable results of photoaging and photodamage.

Phototherapy:

Phototherapy is exposure to nonionizing radiation for therapeutic benefit. It may involve exposure to UVB, UVA or various combinations of UVB and UVA radiation. Photochemotherapy (PUVA) is the therapeutic use of radiation in combination with a photosensitizing chemical. It currently involves the use of psoralens and UVA radiation. Treatment with these modalities may involve partial or whole-body exposure.

Piedra:

Piedra is a fungous infection of the hair shaft, caused by either Piedraia hortae (black piedra) or Trichosporon beigelii (white piedra).

Also see: Fungal Infections

Piercing:

See: Tattoos and Piercing

Pityriasis Alba:

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 moisturiser creams. The condition is so named for the fine scaly appearance initially present and the pallor of the patches that develop.

There is no specific known cause for this condition, but any dermatitis may heal leaving pale skin, as may excessive use of corticosteroid creams used to treat episodes of eczema. The hypopigmentation is due to both reduced activity of melanocytes with fewer and smaller melanosomes.

The condition is most often seen in children between the ages of 3 and 16 years and is more common in males than females. It may occur more frequently in lighter-skinned patients, but is more apparent in those with darker complexions.

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, of 0.5-2 cm in size although may be larger if they occur on the body (up to 4cm), 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 lesions of pityriasis alba tend to have less well-defined borders than lesions seen in vitiligo, and they do not coalesce as seen in tinea versicolor.

No treatment is required and the patches in time will settle. The redness, scale and itch if present may be managed with simple emollients and sometimes hydrocortisone, a weak steroid, is also used.

As the patches of pityriasis alba do not darken normally in sunlight, effective sun protection helps minimise the discrepancy in colouration against the surrounding normal skin. Cosmetic camouflage may be required.

The patches of pityriasis alba may last from 1 month to 10 years, but commonly on the face last a year or more. This is a self-limited disorder that usually resolves by adulthood.

Submitted by: Nitra Cole, MSN, ARNP, NP-C

Pityriasis rosea:

Pityriasis rosea (PR) is a common, harmless skin disease which presents as numerous patches of pink or red oval rash, mainly on the torso. Pityriasis rosea is non-contaigous and non-dangerous. The exact cause of pityriasis rosea is unclear, although the cause may be a viral infection, such as certain strains of the human herpes virus.

PR occurs as large patches of pink or red, flaky, oval-shaped lesions on the torso. A single, large red "herald" patch may occur 1 to 20 days before smaller, more numerous patches of rash. The "herald" patch may be preceded by a sore throat of varying severity.

The more numerous oval patches generally spread widely across the chest first, following the rib-line. Small, circular patches may appear on the back and neck several days later. It is unusual for lesions to form on the face, but they may appear on the cheeks or at the hairline. As the rash begins to subside on the torso, it may spread to the groin and the extremities. These lesions are usually more short-lived.

About one-in-four people with PR suffer from mild to severe symptomatic itching. The rash may be be accompanied by low-grade headache, fever, nausea and fatigue.

No treatment is usually required. In most patients, the condition lasts only a matter of weeks; in some cases it can last longer (up to six months). A doctor should be consulted, if only to rule out other conditions.

In its early stage, however, pityriasis rosea can look like several other skin diseases, including ringworm, eczema, psoriasis or secondary syphilis. Your doctor may order blood tests or a skin biopsy to rule out these conditions.

The overall prevalence of PR in the United States has been estimated to be 0.13% in men and 0.14% in women. It most commonly occurs in those between the ages of 10 and 35.

Though multiple family members have been known to contract the disease at roughly the same time, this may be co-incidental; the fact that PR is far more common in the spring and autumn months points to environmental factors and not person-to-person contact as the main disease vector.

Submitted by: Nitra Cole, MSN, ARNP, NP-C

Pityriasis rubra pilaris:

  • Rare, chronic disease.
  • Unknown cause.
  • May last months to years (80% of patients clear in 3 years).
  • Occurs more frequently in those age 50 - 60 years old, equally between men & women.
  • May occur in children (familial/ autosomal dominant inheritance) (Juvenile type).
  • Severe forms may be associated with HIV.

Description of rash: - Small, red scaling plaque on face or upper body which may enlarge over days or weeks and lead to thickening of palms of hands or soles of feet

Bright red-orange spots may appear on fingers, elbows, knees, trunk of body.

There may be areas of “normal skin” or “skip spots” on the body.

Nails may be yellow-brown, thick, and have small hemorrhages.

Signs & Symptoms: - Little or no itch and/or Painful ulcers to soles of feet may develop.

How it is diagnosed: - Exam and biopsy

Submitted by: Mickelle Riley, MSN, ARNP, NP-C

Pityriasis versicolor:

Pityriasis (tinea) versicolor is a superficial infection of the stratum corneum by the yeast Malassezia furfur (syn. Pityrosporum orbiculare). This yeast is part of the normal cutaneous flora. Pityriasis (tinea) versicolor is characterized by hyperpigmented and hypopigmented scaly patches, primarily on the trunk and proximal extremities. It is a common disorder that affects people of all age groups, but is most commonly seen in adults. Infants and children can also be affected, but often have an atypical presentation. This disease is typically worse in geographic areas with tropical ambient temperatures. Multiple factors are known to contribute to its pathogenesis.

Also see: Tinea

Plantar warts:

See: Warts

Plaque psoriasis:

Psoriasis characterized by red, silvery-white, scaly skin lesions (most common variety of psoriasis).

Also see: Psoriasis

Precursor lesion:

A lesion that has the potential to develop into a melanoma. Precursor lesions include dysplastic nevi, benign compound nevi, small and large congenital nevomelanocytic nevi, and lentigo maligna.

Also see: Melanoma

Primary cutaneous melanoma:

Any primary melanoma lesion, regardless of tumor thickness, in patients without clinical or histological evidence of regional or distant metastatic disease.

Also see: Melanoma, Skin Cancer

Pruritus:

A sensation that provokes the desire to scratch. Itching can be a significant source of frustration and discomfort for patients. When severe, it can lead to loss of sleep, anxiety, and depression.

Psoriasis:

Psoriasis is a noncontagious common condition of the skin that causes rapid skin cell reproduction resulting in red, dry patches of thickened skin. The dry flakes and skin scales are thought to result from the buildup of the rapid production of skin cells. Psoriasis commonly affects the skin of the elbows, knees, scalp, and ears.

Some people have very mild involvement with small dry patches on their elbows, knees, or scalp and may not know they have the disease because it is so mild. Others have very severe disease where virtually their entire body is fully covered with psoriasis.

Psoriasis is considered a long-term (chronic) skin condition. It has a variable course with periodic ups and downs. Sometimes psoriasis may clear for years and stay in remission. Some people have worsening of their symptoms in the colder winter months. Many people report improvement in warmer months, climates, or with increased sunlight exposure.

Psoriasis is seen worldwide, in all races, and both sexes. Although psoriasis can be seen in people of any age, from babies to seniors, most commonly patients are first diagnosed in their early adult years.

Patients with more severe psoriasis may have social embarrassment, job stress, emotional distress, and other personal issues because of the appearance of their skin.

Causes - The exact cause remains unknown. There may be a combination of factors, including genetic predisposition and environmental factors. The immune system is thought to play a major role. Despite research over the past 30 years looking at many triggers, the "master switch" that turns on psoriasis is still a mystery.

Symptoms - Psoriasis typically looks like red or pink areas of thickened, raised, and dry skin. It classically affects areas over the elbows, knees, and scalp. Essentially any body area may be involved. It tends to be more common in areas of trauma, repeat rubbing, use, or abrasions.

Psoriasis has many different appearances. It may be small flattened bumps, large thick plaques of raised skin, red patches, and pink mildly dry skin to big flakes of dry skin that flake off.

There are several different types of psoriasis including psoriasis vulgaris (common type), guttate psoriasis (small, drop like spots), inverse psoriasis (in the folds like of the underarms, navel, and buttocks), and pustular psoriasis (liquid-filled yellowish small blisters).

Sometimes pulling of one of these small dry white flakes of skin causes a tiny blood spot on the skin. This is medically referred to as a special diagnostic sign in psoriasis called the Auspitz sign.

Genital lesions especially on the head of the penis are common. Psoriasis in moist areas like the navel or area between the buttocks (intergluteal folds) may look like flat red patches. These atypical appearances may be confused with other skin conditions like fungal infections, yeast infections, skin irritation, or bacterial Staph infections.

On the nails, it can look like very small pits (pinpoint depressions or white spots on the nail) or as larger yellowish-brown separations of the nail bed called "oil spots." Nail psoriasis may be confused with and incorrectly diagnosed as a fungal nail infection.

On the scalp, it may look like severe dandruff with dry flakes and red areas of skin. It may be difficult to tell the difference between scalp psoriasis and seborrhea (dandruff). However, the treatment is often very similar for both conditions.

Treatment - There are many effective treatment choices for psoriasis. The best treatment is individually determined by the treating physician and depends, in part, on the type of disease, the severity, and the total body area involved.

For mild disease that involves only small areas of the body (like less than 10% of the total skin surface), topical (skin applied) creams, lotions, and sprays may be very effective and safe to use. Occasionally, a small local injection of steroids directly into a tough or resistant isolated psoriasis plaque may be helpful.

For moderate to severe disease that involves much larger areas of the body (like 20% or more of the total skin surface), topical products may not be effective or practical to apply. These cases may require systemic or total body treatments such as pills, light treatments, or injections. Stronger medications usually have greater associated possible risks.

For psoriatic arthritis, systemic medications may be required. Topical therapies are not effective.

It is important to keep in mind that as with any medical condition, all medications carry possible side effects. No medication is 100% effective for everyone, and no medication is 100% safe. The decision to use any medication requires thorough consideration and discussion with your physician. The risks and potential benefit of medications have to be considered for each type of psoriasis and the individual patient. Some patients are not bothered at all by their skin symptoms and may not want any treatment. Other patients are bothered by even small patches of psoriasis and want to keep their skin clear. Everyone is different and, therefore, treatment choices also vary depending on the patient's goals and expressed wishes.

A particularly effective approach to psoriasis has been commonly called "rotational" therapy. This is a common practice among some dermatologists who recommend changing cycles of psoriasis treatments every six to 24 months in order to minimize the possible side effects from any one type of therapy or medication.

For example, if a patient has been using oral methotrexate for two years, then it may be reasonable to take them off of methotrexate and try light therapy or a biologic injectable medication for a while. By rotating to a medication that doesn't affect the liver, the potential of liver damage may be reduced.

In another example, a patient who has been using strong topical steroids over large areas of their body for prolonged periods may benefit from stopping the steroids for a while and rotating onto a different therapy like calcipotriene (Dovonex), light therapy, or an injectable biologic.

Submitted by: Laura L. Mays, PA-C

Psoriatic Arthritis:

A genetically driven autoimmune disease that occurs in less than 10% of persons with psoriasis. Large and small joints are affected. Psoriatic arthritis is often associated with psoriasis in fingernails and toenails.

Pseudoxanthoma elasticum (PXE):

A rare, inherited disease that affects selected connective tissue in some parts of the body. Its incidence has been estimated at 1/25,000-50,000. However, the true incidence is unknown, as it is likely that some patients are so mildly involved that they escape diagnosis and some have atypical presentations. Elastic tissue in the body becomes mineralized, that is, calcium and other minerals are deposited in the tissue. This can result in changes in the skin, eyes, cardiovascular system and gastrointestinal system. Skin changes are sometimes the first indication that a person has pseudoxanthoma elasticum . The affected individual might notice small bumps, or lesions, on the skin. Typically, these skin changes appear first on the sides of the neck and then progress to other parts of the body, but other sites may be involved. The skin lesions are asymptomatic. They do not cause any problems in and of themselves. The definitive tool to diagnose the disorder is a skin biopsy done by a dermatologist.

Pustule:

An inflammatory comedo that resembles a whitehead with a ring of redness around it. A pus-filled pimple.

PUVA:

The acronym for Psoralen + ultraviolet light A. PUVA is a type of phototherapy used in treatment of psoriasis. Treatment requires the patient to ingest, topically apply, or bathe in a medication called psoralen before being exposed to UVA rays.

See: Psoriasis

PXE:

See: Pseudoxanthoma elasticum