Acne, also known as acne vulgaris, is a long-term skin condition that occurs when dead skin cells and oil from the skin clog hair follicles. Typical features of the condition include blackheads or whiteheads, pimples, oily skin, and possible scarring. It primarily affects skin with a relatively high number of oil glands, including the face, upper part of the chest, and back. The resulting appearance can lead to lack of confidence, anxiety, reduced self-esteem, and, in extreme cases, depression or thoughts of suicide.
Dandruff is a skin condition that mainly affects the scalp. Symptoms include flaking and sometimes mild itchiness. It can result in social or self-esteem problems. A more severe form of the condition, which includes inflammation of the skin, is known as seborrhoeic dermatitis.
A sebaceous gland, or oil gland, is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest number on the face and scalp, but also on all parts of the skin except the palms of the hands and soles of the feet. In the eyelids, meibomian glands, also called tarsal glands, are a type of sebaceous gland that secrete a special type of sebum into tears. Surrounding the female nipple, areolar glands are specialized sebaceous glands for lubricating the nipple. Fordyce spots are benign, visible, sebaceous glands found usually on the lips, gums and inner cheeks, and genitals.
Seborrhoeic dermatitis is a long-term skin disorder. Symptoms include flaky, scaly, greasy, and occasionally itchy and inflamed skin. Areas of the skin rich in oil-producing glands are often affected including the scalp, face, and chest. It can result in social or self-esteem problems. In babies, when the scalp is primarily involved, it is called cradle cap. Seborrhoeic dermatitis of the scalp may be described in lay terms as dandruff due to the dry, flaky character of the skin. However, as dandruff may refer to any dryness or scaling of the scalp, not all dandruff is seborrhoeic dermatitis. Seborrhoeic dermatitis is sometimes inaccurately referred to as seborrhoea.
Cutibacterium acnes is the relatively slow-growing, typically aerotolerant anaerobic, gram-positive bacterium (rod) linked to the skin condition of acne; it can also cause chronic blepharitis and endophthalmitis, the latter particularly following intraocular surgery. Its genome has been sequenced and a study has shown several genes can generate enzymes for degrading skin and proteins that may be immunogenic.
Rosacea is a long-term skin condition that typically affects the face. It results in redness, pimples, swelling, and small and superficial dilated blood vessels. Often, the nose, cheeks, forehead, and chin are most involved. A red, enlarged nose may occur in severe disease, a condition known as rhinophyma.
Benzoyl peroxide is a chemical compound (specifically, an organic peroxide) with structural formula (C6H5−C(=O)O−)2, often abbreviated as (BzO)2. In terms of its structure, the molecule can be described as two benzoyl (C6H5−C(=O)−, Bz) groups connected by a peroxide (−O−O−). It is a white granular solid with a faint odour of benzaldehyde, poorly soluble in water but soluble in acetone, ethanol, and many other organic solvents. Benzoyl peroxide is an oxidizer, which is principally used as in the production of polymers.
A comedo is a clogged hair follicle (pore) in the skin. Keratin combines with oil to block the follicle. A comedo can be open (blackhead) or closed by skin (whitehead) and occur with or without acne. The word "comedo" comes from the Latin comedere, meaning "to eat up", and was historically used to describe parasitic worms; in modern medical terminology, it is used to suggest the worm-like appearance of the expressed material.
Demodex folliculorum is a microscopic mite that can only survive on the skin of humans. Most people have D. folliculorum on their skin. Usually, the mites do not cause any harm, so are considered an example of commensalism rather than parasitism; but they can cause disease, known as demodicosis.
Neonatal conjunctivitis is a form of conjunctivitis which affects newborn babies following birth. It is typically due to neonatal bacterial infection, although it can also be non-infectious. Infectious neonatal conjunctivitis is typically contracted during vaginal delivery from exposure to bacteria from the birth canal, most commonly Neisseria gonorrhoeae or Chlamydia trachomatis.
Feline acne is a problem seen in cats primarily involving the formation of blackheads accompanied by inflammation on the cat's chin and surrounding areas that can cause lesions, alopecia, and crusty sores. In many cases symptoms are mild and the disease does not require treatment. Mild cases will resemble dirt on the cat's chin, but the "dirt" will not brush off. More severe cases, however, may respond slowly to treatment and seriously detract from the health and appearance of the cat. Feline acne can affect cats of any age, sex or breed, although Persian cats are also likely to develop acne on the face and in the skin folds. This problem can happen once, be reoccurring, or even persistent throughout the cat's life.
Acneiform eruptions, or acne mimicking eruptions, are a group of skin conditions characterized by small bumps resembling acne. Typically, these bumps are mostly of similar size. Some bumps may be bigger or contain fluid. Generally, blackheads and whiteheads are absent. It tends to appear suddenly, with the chest and back most frequently affected.
Acne conglobata is a highly inflammatory disease presenting with comedones, nodules, abscesses, and draining sinus tracts.
Gnathophyma involves swelling of the chin. It is a type of lesion associated with rosacea, a common chronic inflammatory skin disorder of the sebaceous glands characterized by redness, swelling, and acne-like pustules.
Transient neonatal pustular melanosis (TNPM), also known as pustular melanosis, is a type of neonatal pustular eruption that is a transient rash common in newborns. It is vesiculopustular rash made up of 1–3 mm fluid-filled lesions that rupture, leaving behind a collarette of scale and a brown macule. The lesions are fragile and with no surrounding erythema. This rash occurs only in the newborn stage, usually appearing a few days after birth, but pigmented macules are sometimes already present at birth. The rash usually fades over three to four weeks but may linger for up to three months after birth. It can occur anywhere on the body, including the palms and soles.
A pimple or zit is a kind of comedo that results from excess sebum and dead skin cells getting trapped in the pores of the skin. In its aggravated state, it may evolve into a pustule or papule. Pimples can be treated by acne medications, antibiotics, and anti-inflammatories prescribed by a physician, or various over the counter remedies purchased at a pharmacy.
Infantile acne is a form of acneiform eruption that occurs in infants from 6 weeks to 1 year of age. Typical symptoms include inflammatory and noninflammatory lesions, papules and pustules most commonly present on the face. No cause of infantile acne has been established but it may be caused by increased sebaceous gland secretions due to elevated androgens, genetics and the fetal adrenal gland causing increased sebum production. Infantile acne can resolve by itself by age 1 or 2. However, treatment options include topical benzyl peroxide, topical retinoids and topical antibiotics in most cases.
Childhood granulomatous periorificial dermatitis (CGPD), is a rare benign granulomatous skin disease of unknown cause. The disorder was first described in 1970 by Gianotti in a case series of five children. CGPD is more common in boys than girls.
Neonatal pustular eruptions are a group of disorders characterized by various forms of pustulosis seen in the first four weeks of life.
