Friday, July 6, 2012

Acne vulgaris


Occurs mostly in teenagers.
Peak: late teenagers but may persist till third decade and beyond especially in females.
  • Etiology:

Elevated sebum excretion:
Sebum excretion is necessary for the development of acne but is not sufficient to cause acne on its own.
The main determinants of sebum excretion are hormonal, which accounts for the onset of acne in the teenagers. 
Androgens and  progestogens increase sebum excretion but estrogens reduce it.

Propionibacterium acnes
It colonises the pilosebaceous ducts and acts on lipids to produce a number of pro-inflammatory factors.

Occlusion or blockage of the pilosebaceous unit.

Clinical features

  • Site: usually limited to the face, shoulders, upper chest and back.
  • Greasy skin
  • Open comedones (blackheads) due to plugging by keratin and sebum of the pilosebaceous orifice, or closed comedones (whiteheads) due to accretions of sebum and keratin deeper in the pilosebaceous ducts are evident.
  • Inflammatory papules, nodules and cysts may occur with some lesion.
  • The lesion may be followed by scarring.
  • Mild form
Dominated by presence of comedones.
May be due to exogenous substances like oily cosmetics, chlorinated hydrocarbons, tars, etc
Pustular rash may also be seen in those treated with steroids, lithium, OCP and anticonvulsants.
  • Moderate or Severe form
May have systemic disorder. E.g- polycystic ovarian disease, Androgen secreting tumors




Blackheads & whiteheads

Clinical variants of Acne:

Conglobate acne: 
severe acne with many abscesses and cysts, marked scaring and sinus formation.

2.      Acne fulminans: 
severe acne accompanied by fever, joint pains and markers of systemic inflammation ( raised ESR)

2.      Acne excoriee: 
effect of scratching or pricking, mostly seen on the face of teenage girls with acne.

3.      Infantile acne: 
Rare. It is due to sebotropic effects of maternal hormones on the infant.

Investigation: Rarely reqd.

It is important to enquire about the details of previous treatments and their duration.

Treatment:

1.Fairly minor disease dominated by comedones:
      Topical benzoyl peroxide or tretinoin is used
2.Mild acne: require antibiotics therapy
                       Local antibiotics: Clindamycin or Erythromycin.
                       Oral antibiotics: Oxytetracycline 1.5g per day on empty stomach. If the response is inadequate: Minocycline ( both must be contiued till 3 mnths to see if the antibiotics have worked or not)
                       If little response after 3 mnths treatment: Erythromycin 1g/day.
In women, oestrogen containing OCP can be used as a adjunct in therapy. ( oral estrogen reduces sebum production)
3. If these systemic and topical agents fails to produce an adequate clinical response within 3-6 months;
 Systemic retinoids—isotretinoin (decreases follicular keratinization, Sebum production, bacterial count)

Physical measures
Cysts incised and drained under LA.
Stubborn cysts: intralesional triamcinolone



Rosacea

It is a chronic disorder affecting the facial convexities, characterized by frequent flushing, persistent erythema and telangiectasia, interspersed by episodes of inflammation during which swelling, papules and pustules are evident.






Clinical features

  • The areas characteristically affected are the central convex areas of the face (nose, forehead, cheeks and chin) . Occasionally, the scalp, upper chest, back and even the limbs may be involved. 
  • In cases of rosacea showing the classical pattern of progression, the onset is most often marked by vascular changes, notably episodic flushing usually unaccompanied by sweating.
  • Erythema, which is often accompanied by a burning sensation, gradually becomes more persistent, is easily triggered by minor irritants, and is associated with increasingly prominent telangiectasia.
  • More advanced cases show follicular and nonfollicular papules and pustules, without comedones, followed by persisting tissue thickening due to oedema, fibrosis and glandular hyperplasia, leading ultimately to a peau d’orange appearance and phymas.
  • Factors which trigger flushing include emotion and stress, hot drinks, alcohol and other vasodilating drugs, and spicy food. 
  • Aggravating factors include the use of topical steroids on those occasions when they are used (usually in error) to treat rosacea.
  • Sun exposure may worsen or improve rosacea.
  • Rhinophyma, with erythema, sebaceous gland hyperplasia  and overgrowth of the soft tissue of the nose, is sometimes associates.
  • There may be complications like blepharitis and conjunctivitis.


Treatment

Oral oxytetracycline can be used for the pustular component of rosacea.

Topical metronidazole can also be used.

Erythema and telangiectasia don’t respond to antibiotic therapy.

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