Dermatology Glossary P Q

A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - PQ - R - S - T - UV - WXYZ

Papule
AA raised lesion on the skin that measures no more than 1cm (0.4 inches) at its greatest diameter. Smaller than a nodule or plaque. Referred to as vesicle if filled with fluid.

Patch
A flat spot that appears different from the surrounding skin. Measures more than 1cm (0.4 inches) at its greatest diameter. Larger than a macule.

Peptide
A peptide is a tiny chain of amino acids. These may be used in some skin care products (cosmeceuticals) to prompt the growth of skin cells. Copper peptides can cause brown spots to fade and smooth wrinkles very slightly.

Photoaging
This is the name for premature aging of the skin caused by exposure to the UV rays from sunlight. The symptoms of photoaging include uneven pigmentation, fine lines, and wrinkles. Photoaging is accelerated from exposure to ultraviolet radiation (UV) rays from sunlight or tanning booths.

Learn more about photoaging

Photodynamic therapy (PDT)
This therapy combines a topical medication that makes the skin sensitive to light and a light source . It is used to treat acne , aging skin, and, in selected cases, the early stages of skin cancer. A chemical, aminolevulanic acid, is applied onto the skin. A pulsed dye laser, intense pulsed light (IPL), or blue light is then shown onto the skin. The chemical enhances the effects of the light source.

Photorejuvenation
This refers to the use of light and energy sources, like lasers, intense pulsed light (IPL), and radio-frequency devices, to reduce or eliminate unwanted pigmentation, fine lines, wrinkles, and sagging areas of the skin.

Phytophotodermatitis
A rash that appears when sunlight strikes skin that has been sensitized after it has come into contact with certain plant materials. For instance, lime juice can sensitize the skin so that exposure to sun leads to a rash where the juice made contact.

Pityrosporum folliculitis
The fungi, dermatophyte, that causes tinea versicolor. Another name for Malassezia furfur.

Plaque
A flat, raised lesion on the skin that measures at least 1cm (0.4 inches) at its greatest diameter. Referred to as a nodule if rounded or dome-shaped.

PPX system
This is a painless treatment for acne, also called Isolaz. It uses gentle suction to open and unclog the pores, clean out sebum, expose the skin to intense pulsed light, reduce skin inflammation, and kill the acne-causing bacteria (p. acnes). The treatment is very effective for blackheads, larger acne lesions, and, occasionally, cystic acne. It may also be used to remove unwanted hair and photorejuvenation.

Pruritus
Itching. The sensation that creates the desire to scratch or rub.

Psoriasis
Psoriasis is a chronic, non-contagious skin condition that appears as red scaly patches on the limb, trunk, scalp and other parts of the body. There are 5 types of psoriasis; plaque (the most common), guttate, erythrodermic, inverse, and pustular.

Learn more about psoriasis.

Pulsed dye laser
This type of laser was one of the first used to treat skin conditions. The pulsed dye laser remains the treatment of choice for port-wine stain birthmarks. Newer versions are effective for treating facial blood vessels, redness, flushing, stretch marks, and scars.

Pustule
An elevated lesion, similar to a vesicle, that contains infected fluid and dead white blood cells (“pus”).

Q

Q-switched laser
This is a type of  ultra short-pulsed laser that treats brown spots, birthmarks, and tattoos with minimal discomfort. The alexandrite, ruby, and Nd:YAG are examples of Q-switched lasers that are used in skin treatments.

Return to Top

Last updated December 10, 2009

This information is for general educational uses only. It may not apply to you and your specific medical needs. This information should not be used in place of a visit, call, consultation with or the advice of your physician or health care professional. Communicate promptly with your physician or other health care professional with any health-related questions or concerns.

Be sure to follow specific instructions given to you by your physician or health care professional.

This website is certified by Health On the Net Foundation. Click to verify. This site complies with the HONcode standard for trustworthy health information:
verify here.
View Content Policy