Tretinoin Health Dictionary

A common skin condition starting after puberty, and which may persist for many years. It involves plugged pores (blackheads and whiteheads), pimples and deeper nodules on the face, neck, trunk and even the upper arms. It arises from pilosebaceous glands (relating to hair follicles and associated SEBACEOUS GLANDS). SEBUM production is increased and bacterial proliferation causes in?ammation with PAPULE and PUSTULE formation. Plugs of sebum and epidermal cells form blackheads (comedones); the colour is not due to dirt but to dried oil and shed skin cells in the hair-follicle openings.

Treatment Twice-daily washing with a salicylic-acid cleanser can help remove the pore-blocking debris, as can daily shampooing. Use only oil-free cosmetics and hide blackheads with a ?esh-tinted acne lotion containing benzoyl peroxide, acid or sulphur. Never squeeze blackheads, however tempting; ask a skin specialist how to do this properly. Other treatments include microdermabrasion, and the antibiotic lotions erythromycin and clindamycin may be e?ective. Tretinoin and adapilene can be used on the skin but are not permitted in pregnancy and may cause problems such as hypersensitivity to sunlight, so medical advice is essential. In resistant cases, long-term suppressive oral therapy with one of the TETRACYCLINES or with ERYTHROMYCIN may be necessary. In females a combined oestrogenantiandrogen ‘pill’ is an alternative. Severe resistant acne can be cleared by a 16- to 24week course of oral isotretinoin, but this drug is teratogenic (see TERATOGENESIS) and can cause many side-effects including depression, so its use requires specialist supervision.

See www.skincarephysicians.com/acnenet/... acne

A fat-soluble vitamin essential for normal growth, for the formation of bones and teeth, for cell structure, for night vision, and for protecting the linings of the respiratory, digestive, and urinary tracts against infection.

Vitamin A is absorbed by the body in the form of retinol. This is found in liver, fish-liver oils, egg yolk, dairy produce, and is added to margarines. Carotene, which the body converts into retinol, is found in various vegetables and fruits.

Vitamin A deficiency is rare in developed countries. In most cases, it is due to malabsorption. Vitamin A deficiency may also result from long-term treatment with certain lipid-lowering drugs. Deficiency is common in some developing countries due to poor diet. The first symptom of deficiency is night blindness, followed by dryness and inflammation of the eyes (see xerophthalmia), keratomalacia, and eventually blindness. Deficiency also causes reduced resistance to infection, dry skin, and, in children, stunted growth.

Prolonged excessive intake of vitamin A can cause headache, nausea, loss of appetite, skin peeling, hair loss, and irregular menstruation. In severe cases, the liver and spleen become enlarged. Excessive intake during pregnancy may cause birth defects. In infants, excessive intake may cause skull deformities, which disappear if the diet is corrected.

The drug tretinoin (a derivative of vitamin A) is used to treat severe acne.... vitamin a

n. any one of a group of drugs derived from vitamin A. They bind to one or more of six specific receptors that are found on many cells. On the skin they act to cause drying and peeling and a reduction in oil (sebum) production. These effects can be useful in the treatment of severe *acne, *psoriasis, *ichthyosis, and other skin disorders. Retinoids include *isotretinoin, *tretinoin, acitretin, tazarotene, and alitretinoin, which is particularly effective for hyperkeratotic hand eczema. Possible side-effects, which may be serious, include severe fetal abnormalities (if taken by pregnant women), toxic effects on babies (if taken by breastfeeding mothers), liver and kidney damage, excessive drying, redness and itching of the skin, and muscle pain and stiffness.... retinoid