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« on: September 29, 2012, 04:12:11 PM »
The skin consists of the epidermis and the dermis. The epidermis is composed of five main layers. The dermis consists of two layers.
Tretinoin thins the outermost layer of the epidermis but thickens other layers of the epidermis and thus it thickens the total overall thickness of the epidermis and triggers collagen in the dermis (see the studies below). Of course there is a possibility there can be exceptions to this rule, but they would be very rare.
Tretinoin decreases melanin content. It means, it improves spots and hyperpigmentation but it also means it makes skin less protected from the UV radiation (melanin is skin`s natural UV filter). The darker the skin, the more naturally protected it is. So, you have to apply a sunscreen or use Tretinoin during the winter.
Tretinoin also speeds up the turnover of the skin and thus often improves acne prone skin. Initially, it sometimes make acne worse. You have to persist.
The more is not the better with Tretinoin Do not apply too much. Applying every second day is sufficient, even though daily application.
Initially, Tretinoin makes skin dry. Wrinkles and lines are more visible on dry skin and that is why it may seem in some cases that Tretinoin worsened wrinkles but it did not.
I do not really recommend using Tretinoin on the sensitive skin around the eyes. Our Infadolan ointment that contains Retinyl acetate is more suitable in this area.
Tretinoin has the most dramatic effect on severely sun damaged skin, pigmentations and acne, to certain extent on wrinkles and loss of elasticity.
If you are young, acne free with no pigmentations or post acne spots, there is no reason to apply Tretinoin.
Topical retinoic acid for treatment of solar damage
L. LEVER, P. KUMAR, R. MARKS*
Summary
Twenty patients with chronic solar damage of the skin were entered in a double-blind, withinpatient trial to compare the effect of 0.05% tretinoin cream with a placebo applied once daily for 12 weeks. Sixteen completed the study. Clinical assessment of the individual signs of solar damage were recorded on separate visual analogue scales. After 12 weeks, there were significant improvements in fine wrinkling around the eyes, crease lines around the mouth and cheeks, wrinkling on the dorsum of the hands and yellow discoloration. Overall, 14 of the tretinoin treated sides were judged to have improved compared to only two of the placebo-treated sides (P=0.011). Measurement of skin thickness by pulsed A-scan ultrasound revealed that the sides treated with tretinoin were significantly thicker than the placebo-treated sides(P=0.019). Skin biopsies taken before and after treatment showed an increase in mean epidermal thickness with tretinoin treatment (P=0.019). The clinical signs of improvement persisted at the follow-up assessment performed 4 weeks after cessation of therapy.
Sustained improvement with prolonged topical tretinoin (retinoic acid) for photoaged skin
Charles N. Ellis MD , Jonathan S. Weiss MD , Ted A. Hamilton MS , John T. Headington MD, Alvin S. Zelickson,MD , John J. Voorhees MD
Summary:
We performed a 22-month trial of topical tretinoin (retinoic acid) in the treatment of pho-toaging. Thirty patients participated in a 4-month, randomized, blinded, vehicle-controlled study that has been reported previously; 21 patients continued tretinoin therapy on an open-label basis, participating in the study for a total of 10 months, and 16 patients continued for 22 months. During the open-label study, the statistically significant improvement that had occurred in fine and coarse wrinkling and skin texture during our original study was sustained, despite reductions in dose or frequency of application of tretinoin. The number of discrete lentigines decreased by 71% compared with the number before therapy. Histologic findings included a statistically significant thickening of the epidermis. Side effects were limited to a cutaneous retinoid reaction that diminished as therapy proceeded.
Sarah`s comment: In the study below, Tazaroten (also a potent retinoid, like Tretinoin) was used to ameliorate (lessen) skin thinning caused by Corticosteroids.
A pilot study to determine the effect of tazarotene gel 0.1% on steroid-induced epidermal atrophy:
1. Kays Kaidbey MD,
2. Scott C. Kopper BS,
3. John Sefton PhD,
4. John R. Gibson MD
Results: The mean epidermal thickness was increased by 20% (NS) and 62% (P ≤ 0.0005) after applications of tazarotene vehicle and tazarotene gel 0.1%, respectively. Application of diflorasone diacetate reduced the mean epidermal thickness by 43% (P ≤ 0.0005). Concomitant application of tazarotene gel 0.1% with diflorasone diacetate did not entirely prevent atrophy, but was shown to ameliorate 37% of the epidermal atrophy induced by diflorasone diacetate alone (P ≤ 0.003 compared with steroid monotherapy).
Conclusions Tazarotene gel 0.1% significantly reduces epidermal atrophy induced by diflorasone diacetate 0.05% ointment.
Treatment of photodamage with topical tretinoin: an overview
Gilchrest BA
Department of Dermatology, Boston University School of Medicine, MA 02118, USA.
Journal of the American Academy of Dermatology [1997, 36(3 Pt 2):S27-36]
Summary:
Topical administration of tretinoin has proved to be effective in treating clinical signs of photodamaged skin. In large-scale, double-blind, placebo-controlled, 6-month trials, 0.05% tretinoin emollient cream (Renova, Retinova) reduced fine wrinkles and skin roughness, and it produced histologic changes such as epidermal thickening, increased granular layer thickness, stratum comeum compaction, and decreased melanin content. Smaller changes were also observed at lower tretinoin concentrations. Continued for another 6 months, 0.05% tretinoin emollient cream produced some additional clinical improvement but the histologic changes observed in the epidermis (with the exception of melanin content) regressed toward baseline, raising questions as to what was responsible for the clinical improvement. After 12 months of treatment, there were additional signs of tissue normalization including deposition of new collagen in the papillary dermis and ultrastructural evidence of dermal reconstruction with improvement in the dermoepidermal junction and correction of keratinocyte degeneration, changes that presumably relate directly to tretinoin's mechanism of action. There was no suggestion of cytologic atypia in these studies or in biopsy specimens obtained after up to 4 years of continued use. Mild to moderate dermatitis was the only common adverse reaction to tretinoin use. Percutaneous tretinoin absorption is low, raising plasma levels by amounts that are negligible compared with the normally low endogenous tretinoin levels. No teratogenic effects have been observed in retrospective studies of topical tretinoin application during the first trimester of pregnancy. Thus, topical tretinoin is safe and effective in the treatment of photodamage.
Sarah`s comment: In spite that the above study states that Tretinoin is safe in pregnancy, you should not apply it right after dermarolling/needling /stamping when pregnant, lactating or planning a pregnancy. All these microneedling tools greatly enhance its absorption. The risks are still minimal, but better safe than sorry.
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