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Issue
38 — March 2005 |
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Acne
is a frequently occurring skin disease: about 80 percent of the adolescents suffer
from acne during puberty (1). Although it is no serious health hazard, except
in some rare severe forms, acne impairs the attractiveness and therefore has negative
effects on the self-confidence. Boys are more and longer affected by acne than
girls (2). The first symptoms of acne may already occur in 8 or 9 year old children
but usually become apparent at early teenage. Acne normally disappears after puberty
but may persist or reappear in some cases in the fourth decade (3). An overview
of the various forms of acne is shown in Figure 1.
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Figure
1: Forms of acne
- Acne comedonica
- Acne papulo-pustulosa
- Acne conglobata
- Acne tarda (adults)
- Excoriated acne
- Acne cosmetica
(caused by comedogenic ingredients in cosmetic products)
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Development and symptoms of acne
Acne is caused by changes in the sebaceous glands. Male hormones, the androgens,
the secretion of which sets on both in boys and girls in puberty, enhance the
sebum production (4). This leads to enlarged pores and to oiliness of the skin,
especially in areas with high densities of sebaceous glands like forehead, nose,
chin, upper arms, upper back, and breast (5). Concomitant with the induction of
an increase in sebum production, androgens also lead to a disturbed maturation
of the skin cells in the infundibulum, the secretion duct of the sebaceous gland.
Normally, individual corneocytes are shed from the lining into the lumen of the
infundibulum after all intercellular connections have been cut during the maturation
process. In acne, however, adjacent corneocytes are still linked to one another
at the surface due to a disturbance in maturation. This leads to the shedding
of large cell clusters which, together with excessive sebum, block the pores (6).
Such a whitish plug – a whitehead – is the first stage of a comedone.
Sebum accumulating beneath the plug causes the whitehead to rise slightly above
the skin level. Initially it is covered thinly and therefore called a closed comedone.
After the cover is disrupted, oxidization processes of proteins and lipids together
with melanin contained in the corneocytes produce a dark colouring – the
blackhead, or open comedone (7) (see Figure 2). The majority
of comedones remains at the stage of whitehead or blackhead until the plug is
spontaneously shed in the course of the normal skin turn-over, or by cosmetic
or medical treatment. In mild forms of acne, comedones are often the only symptoms
(Acne comedonica (5)). Certain cosmetic ingredients, especially oils and emollients,
can stimulate the formation of comedones, they are comedogenic. Classifications
of comedogencity of cosmetic ingredients are not very reliable. Existing lists
are based on tests on rabbit ears without a proven correlation with the situation
on acne-prone human skin (8).
The excessive proliferation of certain skin bacteria,e.g. Propionibacterium acnes,
in the comedones induces the accumulation of some inflammatory metabolic products
(9). The tissue surrounding the affected follicle swells, erythema develops, and
pus is formed in the gland (4). Inflammations in deeper layers form red nodules,
superficial ones are visible as purulent pustules. The term Acne papulo-pustulosa
(5) defines forms of acne where several of such inflammatory lesions are present
besides the comedones. Please also see Figure 3 for the various
symptoms of acne.
Figure
2: Development of comedones
Prerequisites
- Oily skin with
increased sebum production
- Disturbed maturation
of skin cells in the follicles
Lumps of adhering
dead skin cells and sebum:
Result
- Plug of sebum and
dead skin cells in the pore, first white (whitehead), then black through
oxidation (blackhead)
Blackhead
(comedone):
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Figure
3: Symptoms of acne
Fotos thanks
to Dr. Darinka Keil, Bad Dürkheim |
The physiological defence systems are usually well able to induce a rapid healing
of the inflammation: the papule or pustule dries up and the erythema disappears
within a few days. What remains is often only an enlarged pore. Improper manipulations
in attempts to squeeze out the papules and pustules, by contrast, induce lasting
skin damage. Often, the pressure applied leads to the rupture of the sebaceous
gland beneath the skin surface, liberating its content of pus, living and dead
bacteria, sebum, and its bacterial metabolites into the surrounding tissue. Thus
the inflammation spreads and is aggravated (Figure 4). The
healing of such an enlarged effect is prolonged as compared to the normal process
and often leaves permanent scars which can only be removed by surgical resurfacing.
Especially young woman tend to deteriorate their otherwise mild acne by such manipulations.
Such a phenomenon is termed acne excoriée de la jeune fille (3).
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Figure
4: Development of inflammatory acne lesions from comedones
Within the plugged sebum glands skin bacteria like Propionibacterium
acnes proliferate. Their metabolic products induce inflammation of the
walls of the sebum gland (follicle).
The follicle swells and becomes red. Pus develops.
Attempts to squeeze out the pimples disrupt the walls of the sebum gland.
Pus, bacteria, and metabolites spread the inflammation in the surrounding
tissue.
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Only a small percentage of people affected by acne develop severe forms with a
multitude of inflamed lesions or extensive, nodular inflammations. Such stages
require dermatological treatment to avoid permanent scarring (3).
Medical and mechanical treatment of acne
The therapy of acne has to be adapted to the quality and severity of the symptoms.
No treatment shows immediate or even short-term effects. This impairs the patients’
compliance, especially in adolescents. By rapidly changing from one cosmetic preparation
to the other acne skin can become irritated or damaged.
Mild forms of acne can be treated efficiently by adequate skin cleansing and care
(10). Severe forms and highly inflammatory processes require medical therapy which
can be supported by the application of suitable cosmetic products (7, 11, 12).
For medical acne therapy externally applied keratolytic or disinfectant preparations,
e.g. with benzoyl peroxide or triclosan, are often used in a first step. They
are able to resolve the plugs of sebum and corneocytes or eliminate the bacteria,
respectively. Mild keratolytic preparations termed as peelings are used as cosmetic
products for acne. Another widespread group of acne therapeutics are antibiotics,
like erythromycin or minocyclin, which can also be administered systemically in
severe forms. retinoic acid and its derivates, e.g. isotretinoin, are able to
reduce the overproduction of sebum as well as normalize the maturation process
of the corneocytes in the infundibulum. They can be used externally or systemically.
In young women, secure contraception is necessary as these substances are teratogenic.
Antibiotics and retinoic acid derivatives increase the UV sensitivity of the skin.
The skin therefore requires efficient sun protection. An efficient treatment is
also possible with systemically applied anti-androgens. They abolish the androgen-induced
changes in corneocyte maturation and the increased sebum production and mediate
a contraceptive effect. They can be used by women only.
Medical treatment of acne often causes dry and sensitive skin. Adequate skin care
with preparations low in or free of oils is required to alleviate the symptoms
of tension, roughness, erythema, or flaking of the skin without deteriorating
acne.
Dermatologists and cosmeticians offer a mechanical acne treatment, where comedones
and pustules are removed by gently opening and emptying them under sterile conditions
after prior softening and dissolving the plugs in the infundibulum without damage
to the surrounding skin tissue (7).
Skin cleansing in acne
Normal soaps are not well suited for acne skin (13). They induce skin swelling
which hinders thorough cleansing, favouring the development of comedones. Their
pH of 8-12 destroys the physiological acid mantle of the skin. This leads to an
enhanced proliferation of acne bacteria and thus to the development of more inflamed
lesions. Soap-free cleansing preparations with a pH of 5.5, adjusted to the acid
mantle of the skin can be formulated with mild surfactants to provide mildness,
while inhibiting the acne bacteria by supporting the acidic milieu on the skin
surface13. In the presence of many inflammatory acne lesions as a sign of the
presence of excessive acne bacteria, the inclusion of anti-bacterial additives
or cationic surfactants with an anti-bacterial effect like Montaline C40 (INCI:
Cocamidopropylalbetainamide MEA Chloride) in skin cleansing products is helpful
(14). A pH of 5.5 in such formulations additionally inhibits the repopulation
of the skin Propionibacterium acnes.
Excessive cleansing procedures are common among people suffering from acne but
they have no positive effects. For hygienic purposes it is fully sufficient to
wash in the morning and the evening. Additional cleansing procedures may dry out
and irritate the skin, causing feelings of tension, roughness, redness, and flaking.
Irritations also aggravate the disturbed maturation of the corneocytes and thus
induce more comedones.
It is recommendable to include an additional cleansing step with a toner containing
alcohol after washing for very oily skin and skin areas with high densities of
comedones and pustules. To avoid skin dryness and irritation such toners should
contain moisturizers and anti-irritant ingredients like e.g. hydrolyzed silk,
cucumber extract, bisabolol, or hamamelis.
Peeling
Peelings are often recommended for the cosmetic treatment of comedones. Like keratolytic
drugs, they remove the superficial layers of the Stratum corneum. This applies
for mechanical and chemical peelings, e.g. alpha-hydroxyacids (AHA like lactic
acid, pyruvic acid, or glycolic acid) and beta-hydroxyacids (like salicylic acid)
alike. Frequently repeated peeling or preparations with pH below 5 reduce the
barrier function of the skin with subsequent dehydration and enhanced sensitivity.
Often, adhesive tapes with peeling substances are used. They remove many of the
existing comedones but cannot prevent the formation of new ones.
Skin care in acne
Tension, roughness, redness, and flaking after skin cleansing are indicative for
the necessity of skin care. An overview of the various forms of skin care in acne
is given in Figure 5. First of all the cleansing procedures
should be reconsidered and milder cleansing products, lower dosage and water temperature
or reduced frequency of the use of toners or peelings should be applied.
Often, persons with acne want or need to use skin care products. Especially women
like to apply skin care products. In cases of Acne tarda and when drug therapy
is applied the dryness of the skin care is often necessary to alleviate dryness.
However, oily creams and lotions should be avoided. Best suited are hydrogels
without oils or emollients. Their moisturizers relieve skin tension and provide
smoothness. Additional active ingredients like aloe or bisabolol can soothe irritations
in sensitive skin. Panthenol hydrates the skin and also promotes healing of the
acne lesions. Hydrogels can also be used as a make-up foundation, although they
should be absorbed completely before make-up is applied.
In skin care the pH is even more important than in cleansing as the exposure is
not time-limited by rinsing. Therefore the pH of skin care products has a long-lasting
influence (15). A slightly acidic pH does not only inhibit the proliferation of
acne bacteria (13), but also supports the barrier function against dehydration
and irritation.
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Figure
5: Skin care in acne
- Skin cleansing
soap free, pH value 5,5, pore-deep, not too much lipid removal, anti-bacterial
additives may be beneficial
- Deep cleansing
for oily skin and areas with many inflammatory lessions, with alcohol,
with skin care additives
- Peeling
acts against comedones; increases dryness and sensitivity
- Skin care
no oils or emulsifiers, pH 5,5, with soothing and regenerative additives
- Immediate action
against pimples
with anti-bacterial additives and alcohol, anti-inflammatory and healing
additives
- Covering
Sticks and creams with pigments, tinted day creams, make-up, camouflage
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To accelerate the healing of inflammatory acne lesions, anti-pimple sticks, gels
or creams can be used. They are applied only to the lesion and its immediate surroundings,
but not on larger areas. For such preparations, the inclusion of alcohol is helpful,
as it dries out the pustule, and has a disinfectant effect. Other anti-bacterial
substances support the latter effect. Active ingredients with anti-inflammatory
and regenerative effects can also contribute to the rapid disappearance of the
lesion. Usually, it is sufficient to apply the anti-pimple products twice daily.
More frequent use may irritate the skin. Pigments included in such products can
cover the lesion immediately, even before the healing sets in. Therefore, they
are often used in anti-pimple preparations as an immediate aid. Pigmented anti-pimple
creams or sticks usually are emulsions because the pigment cannot be sufficiently
dispersed in hydrogels.
To cover the pustules and comedones in the face, skin tone day creams or covering
sticks are often sufficient. Highly inflammatory or widespread lesions, however,
require camouflage products. All products used to cover acne lesions should contain
only small amounts of oil and be free of comedogenic substances. They have to
be removed thoroughly in the evening before going to bed.
Further factors influencing acne
Nutrition, cigarette smoking, alcohol and sexual habits have no major influence
on acne (5) – contrary to the widespread belief. By contrast, stress is
an established aggravating factor. UV radiation from the sun or solarium often
has a negative effect, even though in some cases it alleviates the inflammatory
lesions (5). The most dominant effect is mediated by endogenous or exogenous hormones
(3).
Conclusion
Acne skin requires special skin care, adapted to the severity and symptomatic
features of the disease and its medical treamtent. For skin cleansing, soap-free
slightly and slightly acidic preparations should be used. A strong lipid removal
is not advisable due to the risk of dehydration and irritation. Disinfectant or
anti-bacterial additives can be of benefit. An additional cleansing step with
alcoholic toners for very oily skin or skin areas severely affected by acne lesions
should be applied with limitations. Peelings should also be used carefully to
avoid irritation. For skin care, oil and emollient-free hydrogels are best suited.
They counteract dehydration caused by cleansing and medical therapy while avoiding
the aggravation of acne process by comedogenic effects.
Patience is required in waiting for medical as well as cosmetic treatment of acne
to take visible effect. Rash termination of the treatment and frequent changes
of preparations is as deleterious as the improper manipulation of the acne lesions.
References
(1) F Daniel, B. Dreno, F.Poli, N. Auffret, C. Beylot, I. Bodokh, M. Chivot, P.
Humbert, J. Meynadier, P. Clerson, R. Humbert, J.P. Berrou, R. Dropsy. [Descriptive
depidemiological study of acne on scholar pupils in France during autumn 1996].
Ann Dermatol Venereol 127: 273-278, 2000
(2) B. Dreno, F. Poli: Epidemiology of acne. Dermatology 206: 7 - 10, 2003
(3) O.Braun-Falco, G.Plewig, H.H.Wolff: Dermatologie und Venerologie. 4.Aufl.
Springer Berlin: 947-962, 1996
(4) U. Jappe: Akne und die Propionibakterien. Pathogenese-orientierte Therapie.
Der Deutsche Dermatologe 9: 583 - 589, 2002
(5) A.M. Grunewald. Klinisches Bild der Akne. Teil 1: Altersabhängige variable
Ausprägungen. TW Dermatologie 23: 395-402, 1993
(6) G. Plewig , A. Kligman, Acne and Rosacea. 3rd Edition, Springer 2000
(7) A.Shai, H.Maibach, R.Baran. Handbook of cosmetic skin care. 81-100, Martin
Dunitz London 2001
(8) A.C. Katoulis, E.M. Kakepis, H. Kintziou, M.E. Kakepis, N.G: Stavrianeas.
Comedogenicity of cosmetics: A review. J. Europ. Acad. Dermatol. Venereol.7: 115-119,
1996
(9) N. .Y. Schürer: Die fette Haut. H + G 68: 636 - 640, 1993
(10) H.C. Korting, E. Ponce-Pöschl, W.Klövekorn, G. Schmötzer,
M. Arens-Corell, O. Braun-Falco. The influence of the regular use of a soal or
an acidic syndet bar on pre-acne. Infection 23: 89-93, 1995
(11) H.C. Korting, W.Sterry (Hrsg.). Therapeutische Verfahren in der Dermatologie.
Blackwell Berlin 2001
(12) R.Baran, M. Chivot, A.R. Shields. Acne. In: R.Baran, H.I. Maibach (Eds.):
Textbook of cosmetic dermatology. 2nd Ed. 433-444. Martin Dunitz London 1994
(13) M.H. Schmid, H.C. Korting. The concept of the acid mantle of the skin: Its
relevance for the choice of skin cleansers. Dermatology 191: 276-280, 1995
(14) D. Keil, E.G. Jung, C. Bayerl. Effects of a mild detergent syndet cleanser
for mild acne on skin barrier function. Ann Derm Venereol, 129: S 377, 2002
(15) W. Gehring, M. Gloor. Neue Aspekte zur Modulation einer reduzierten Barrierefunktion.
H+G 74: 531, V28, 1999
Author
Dr. rer. nat. Michaela Arens-Corell, with Sebapharma GmbH & Co. KG since 1992,
studied Biology and received a doctorate there. After research in the pharmaceutical
industry she became active in skin care and is now head of Sebapharmas' Medical-scientific
Department. As far as the Sebamed products are concerned, her findings of skin
research there yield into product development, marketing, public relations and
consumer care.
