Dandruff.

Published 14/07/2009

22 Votes

What is dandruff and what are its related problems?

It is a flaking condition of the scalp in which various corneal cells clump together resulting in an acceleration of the replacement of epidermal cells.

It is infrequent in infancy but increases progressively from adolescence.  By the age of 20, some 50% of the population have suffered from an outbreak of dandruff, which gives an idea of its frequency.  Although the causes of dandruff are complex and disputed, it is advisable to consider the elements which act jointly in its appearance, in order to understand the treatments used for its correction:

Acceleration of mitosis

A scalp with dandruff carries out the transition of its cells, from the basal stratum to the corneal stratum, in half the time (7 to 10 days) needed for a non-affected scalp (21 days).

Parakeratosis

This abnormal proliferation not only provokes a greater production of corneal cells but also an imperfect differentiation of the keratinocytes, which dictates the accumulation of cells with nucleus (parakeratosic) in the corneal stratum.  There is also an incorrect adhesion of corneocytes which causes a visible flaking of large groups of corneal cells.
The scales or flakes that disperse may be dry or covered in a film of sebaceous secretion.

Increase in seborrhea

In quite a lot of cases both dandruff and seborrhoea coexist on the scalp.  But on other occasions they are exclusive; in such a way that dandruff will disappear to give way to seborrhoea.

Local proliferation of fungal flora (Pityrosporum ovale)

It is disputed whether Pityrosporun ovale is a causal agent or whether it is an opportunistic agent that proliferates excessively in a flaking profile, aggravating the situation.  If this were the case, this fungus could degrade, through the action of extra-cellular enzymes, sebaceous triglycerides (sebum), increasing the level of existing free fatty acids on the scalp, which due to their irritant capacity, would provoke a stimulation of the epidermal proliferation processes (flaking through irritative lipolysis).

Types of dandruff

There are various types of dandruff, with the two most common being dry dandruff and oily dandruff.

Dry dandruff or Pityriasis simplex

Is the most common flaking condition and tends to be present for long periods of time.  If not treated it may become recurrent and even evolve into oily dandruff.
Occasionally it disappears spontaneously- Its principal characteristics are:

1. Presence of fine flakes, white or greyish, which fall off easily and occupy the total area of the scalp.
2. The scales are dispersed unattractively around the neck and shoulders.
3. Dry scalp and lacklustre hair. It does not present any inflammatory signs and pruritus is moderate or absent.

Oily dandruff or Pityriasis steatoide

Is a flaking condition associated with the existence of seborrhoea, which may occur in pityriasis simplex or it may arise spontaneously- Its most notable characteristics are:

1. Presence of larger flakes, thick, yellowish and oily, preferably located in seborrheic areas (frontal scalp). The flakes stick to the scalp and hair, forming plaques.
2. Oily scalp with greasy flaking. It may present accompanied by a reddening of the skin, with more or less intense itching, and inflammation of the scalp. For this reason it is frequently associated with seborrheic dermatitis which affects the auditory channels, midfacial regions (eyebrows, sides of the nose) and sternal region. It may be the cause of alopecia (hair loss).

© Medios Especializados

Rise