Dermatitis is a group of diseases that result in inflammation of the skin. These diseases are characterized by itchiness, red skin and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can vary from small to covering the entire body.
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 anxiety, reduced self-esteem, and, in extreme cases, depression or thoughts of suicide.
A sebaceous 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, also known as seborrhoea, is a long-term skin disorder. Symptoms include red, scaly, greasy, 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. Dandruff is a milder form of the condition without inflammation.
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.
Malassezia is a genus of fungi. Malassezia is naturally found on the skin surfaces of many animals, including humans. In occasional opportunistic infections, some species can cause hypopigmentation or hyperpigmentation on the trunk and other locations in humans. Allergy tests for this fungus are available.
Cutaneous T cell lymphoma (CTCL) is a class of non-Hodgkin lymphoma, which is a type of cancer of the immune system. Unlike most non-Hodgkin lymphomas, CTCL is caused by a mutation of T cells. The cancerous T cells in the body initially migrate to the skin, causing various lesions to appear. These lesions change shape as the disease progresses, typically beginning as what appears to be a rash which can be very itchy and eventually forming plaques and tumors before spreading to other parts of the body.
Acne keloidalis nuchae is a destructive scarring folliculitis that occurs almost exclusively on the occipital scalp of people of African descent, primarily men.
Perioral dermatitis, also known as periorificial dermatitis, is a common type of skin rash. Symptoms include multiple small (1–2 mm) bumps and blisters sometimes with background redness and scale, localized to the skin around the mouth and nostrils. Less commonly the eyes and genitalia may be involved. It can be persistent or recurring and resembles particularly rosacea and to some extent acne and allergic dermatitis. The term "dermatitis" is a misnomer because this is not an eczematous process.
Glochids or glochidia are hair-like spines or short prickles, generally barbed, found on the areoles of cacti in the sub-family Opuntioideae. Cactus glochids easily detached from the plant and lodge in the skin, causing irritation upon contact. The tufts of glochids in the areoles nearly cover the stem surfaces of some cactus species, each tuft containing hundreds of glochids; this may be in addition to, or instead of, the larger, more conspicuous cactus spines, which do not readily detach and are not generally barbed.
Cheilitis is a medical condition characterized by inflammation of the lips. According to its onset and course, cheilitis can be either acute or chronic. Most cheilitis is caused by acute sun exposure. Allergic tests may identify allergens that cause cheilitis.
Persistent edema of rosacea is a hard, nonpitting edema found on the areas involved, those mainly being the forehead, glabella, upper eyelids, nose, and/or cheeks.
Id reactions are types of acute dermatitis developing after days or weeks at skin locations distant from the initial inflammatory or infectious site. They can be localised or generalised. This is also known as an 'autoeczematous response' and there must be an identifiable initial inflammatory or infectious skin problem which leads to the generalised eczema. Often intensely itchy, the red papules and pustules can also be associated with blisters and scales and are always remote from the primary lesion. It is most commonly a blistering rash with itchy vesicles on the sides of fingers and feet as a reaction to fungal infection on the feet, athlete's foot. Stasis dermatitis, allergic contact dermatitis, acute irritant contact eczema and infective dermatitis have been documented as possible triggers, but the exact cause and mechanism is not fully understood. Several other types of id reactions exist including erythema nodosum, erythema multiforme, Sweet's syndrome and urticaria.
Silicone granulomas are a skin condition that occur as a reaction to liquid silicones, and are characterized by the formation of nodules.
Benign cephalic histiocytosis not to be confused with "Neonatal cephalic pustulosis" is a rare skin condition affecting boys and girls equally, characterized by skin lesions that initially present on the head in all cases, often the cheeks, eyelids, forehead, and ears.
Idiopathic facial aseptic granuloma is a cutaneous condition characterized by a chronic, painless, solitary nodule, reminiscent of an acne nodule, appearing on the cheeks of young children. It has a prolonged course, but spontaneously heals.
Sapienic acid is a fatty acid that is a major component of human sebum. Sapienic acid is a sebum fatty acid that is unique to humans. The equivalent fatty acid in mouse sebum is palmitoleic acid.
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.
