Chapter: Medicine Study Notes : Skin


Inflammatory disease occurring in and around the sebaceous glands, generally affecting the face, also the chest and back.



·        Inflammatory disease occurring in and around the sebaceous glands, generally affecting the face, also the chest and back. Characterised by papules and pustules, or by cyst and other more specific lesions. Deeper lesions are associated with scarring: hypertrophic, keloidal or depressed


·        Differential:

o   Rosacea

o   Perioral dermatitis

·        Acneiform drug eruptions




·        Four factors:


o  Increased sebum production by the sebaceous glands (normally produced to maintain epidermal hydration)


o   Cornification (®blockage) of the pilosebaceous duct: abnormal keratinisation and desquamation of follicular epithelium combine with increased amounts of sebum production to obstruct the duct.


o  Bacterial proliferation - abnormal colonisation of the follicle duct by Propionibacterium acnes. But severity not proportional to number of bacteria

o  Inflammation


·        If the obstruction is closer to the skin surface it will form open comedo and oxidation of the fatty material causes discoloration (blackhead). A closed comedo (white head) occurs when the duct is blocked at a deeper level


·        Acne is dependent on:

o  Genetic factors (high concordance in monozygotic twins)

o  Hormonal factors: androgens ® sebum production


o  Environmental factors: aggravated by humidity, some cosmetics and oils (block pilosebaceous orifice)


o  Diet rarely implicated

·        Usually starts in adolescence and resolves by mid 20s (starts earlier in females and is more persistent)




·        Reassurance: Treat as a physical and psychological disorder. Undermines patient‟s self-confidence, especially in the adolescents. Myths of poor diet and hygiene make patients feel responsible and/or guilty - reassured that they are not the cause


·        General advice:

o  Avoid humid conditions

o  Avoid occlusive creams and sunscreens

o  Only use moisturisers if the skin is dry

·        Topical agents.  For mild to moderate acne:


o  Comedolytics: most effective option is Tretinion. Normalises desquamation of the follicular epithelium promoting drainage of pre-existing comedones. This increases penetration of antimicrobial agents


o  Antibiotics such as benzoyl peroxide and erythromycin gel reduce bacterial numbers and inflammation

·        Oral agents. Are generally used for severe or persistent acne in addition to topical agents:


o  Antibiotics such as tetracycline, doxycycline, trimethoprim and erythromycin suppress inflammation by inhibiting neutrophil chemotaxis and production of bacterial lipases and proteases. For a minimum of six months with an 80-90% improvement expected after this time. Often recur. SE of Minocycline: vertigo, discolouration of teeth, grey skin pigmentation


o   Oestrogens. They have a direct effect on sebaceous gland activity. They are combined with progesterone in an oral contraceptive, which may counteract the effects of the oestrogen


o  Antiandrogens (in a female only) such as cyproterone acetate and spironolactone act peripherally to inhibit androgen stimulation of sebaceous glands and hair follicles. They are useful in mature presenting acne


o  Isotretinoin (Roaccutane)


§  A synthetic Vitamin A derivative that inhibits sebaceous gland activity, reduces P. acnes cell numbers, alters follicular keratinisation and is anti-inflammatory

§  At adequate doses permanently cures acne in 80% of cases after 4 – 6 months 

§  Highly teratogenic. Women need to be fully informed of the risks, need to have a negative pregnancy test before starting treatment, and need to be on reliable contraception throughout course (i.e. belt and braces) and one month after 

§  Causes liver damage and hyperlipidaemia: baseline bloods and then after one month

§  Causes dry lips and maybe nasal mucosa (® epistaxis), skin and eyes, angular cheilitis

§  < 10% will get aching muscles, depression, hair loss, headaches



·        Cardinal signs in order of importance:

o   Erythema

o   Telangiectasia

o   Papules

o   Swelling

o   Tiny pustules

·        On cheeks, chin, forehead, nose and neck, sun exposed sites.  Flushing may precede other signs

·        Many theories

·        May be associated with rhinophyma (bullous swelling of the nose)

·        Minor ocular involvement in 50%: especially conjunctivitis, may blepheritis, etc

·        Treatment:

o   Systemic or topical antibiotics (as per acne)

o   Retinoids

o   Metronidazole


Perioral Dermatitis


·        Mainly young women

·        Cause a mystery.  ?Steroids implicated 

·        Starts in nasolabial fold and spreads to involve the perioral area. Minute papules and pustules on an erythematous base with some scaling

·        Treatment: Systemic tetracyclines or erythromycin until rash gone then for another couple of weeks


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Medicine Study Notes : Skin : Acne |

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