Steroid-induced dermal atrophy: effects of glucocorticosteroids on collagen metabolism in human skin fibroblast cultures

Saline in Dermatology: A literature review

BACKGROUND

Saline, with its different concentrations, is the most used crystalloid solution in medicine. In dermatology, no large studies investigated the benefits of saline. The aim of this article is to review the different possible uses of saline in dermatology, in order to give final recommendations based on the literature review and our experience.

METHODS

We performed a literature search based on PubMed, EMBASE, WHO Global Health Library, Virtual Health Library, Web of Science, Scopus, Google Scholar, and Research gate. using the keywords: saline, physiological, hypertonic, isotonic, hypotonic, salt solution, sodium chloride, 0.9% NaCl, solvent, drug delivery, injection mixtures, diluent, sclerosant, intravenous, intralesional, injection, topical, soaks, fomentation, inhalation, alopecia, psoriasis, scars, atopic dermatitis, eczema, bromoderma, iododerma, lipodystrophy, in various combinations with the Boolean operators AND, OR and NOT. We also hand-searched textbooks.

RESULTS

Saline was used as a diluent with intralesional injection of steroids to minimize the risk of steroid-induced atrophy, being safe and free from preservatives that may precipitate steroids at site of injection and maximize their side effects. Saline has also been used after surgery, when atrophic scars take place or anticipated, and through injection in leishmaniasis, granuloma annulare, atrophic acne scars before using other expensive and less tolerated treatment options.

CONCLUSIONS

The saline represents a helpful option as a diluent with intralesional injection of steroids in various dermatologic therapeutic indications. Moreover, the use of saline in this setting could help to minimize the risk of steroid-induced atrophy. We encourage the use of saline after surgery, when atrophic scars take place or anticipated. Also, we encourage a trial of saline injection in leishmaniasis, granuloma annulare, atrophic acne scars before using other expensive and less tolerated treatment options.

Multiple subcutaneous haematomas of the legs causing skin necrosis in an elderly patient affected by corticosteroid-induced skin atrophy: Case report and review of literature

Corticosteroid-induced skin atrophy (CISA) consists of a thinning of the skin and subcutaneous tissues, representing the natural consequence of a prolonged glucocorticosteroids use, both systemic as well as topical. It is characterised by the loss of elasticity and skin thickness, associated with an increased skin fragility leading to ecchymoses, haematomas, and steroid purpura. The management of CISA is a challenge for physicians, as the pathology is reversible in a minimal percentage of cases and only after a short topical steroid or low-dose course therapy. Often wounds with large loss of substance represent the more common complication, after a surgical drainage which is often necessary. Skin necrosis with compartment syndrome of a leg is another potential risk for these patients. Here, we report a case of an elderly patient affected by multiple subcutaneous haematomas of the legs causing skin necrosis, arisen after the use of anticoagulants for a deep venous thrombosis. The patient was successfully treated with surgical drainage, negative pressure wound therapy (NPWT), and porcine xenograft with no complications. Finally, we discuss the evidence of the current literature on topic.

Hydrocortisone effect on hyaluronate synthesis in a self-assembled human dermal equivalent

Human dermal matrix is a 'self-assembled' dermal equivalent containing large amounts of the glycosaminoglycan hyaluronic acid (hyaluronate, hyaluronan, HA). We sought to investigate the actions of the hormone hydrocortisone on hyaluronate synthesis in the human dermal matrix. To this end, human dermal fibroblasts were cultured under serum-free conditions, and in the absence of a three-dimensional matrix, in the presence of varying amounts of hydrocortisone. The resultant human dermal matrices were characterized. We report that low concentrations of hydrocortisone enhance hyaluronate synthesis in the human dermal equivalent and higher concentrations cause inhibition of hyaluronate synthesis. Other glycosaminoglycan (chondroitin sulphate) synthesis is not affected by changing hydrocortisone concentrations up to 500× (200 µg/ml) of the base value. In order to gain preliminary insight into the molecular mechanism of hyaluronate inhibition, a differential gene array analysis was conducted of human dermal matrix grown in the presence of 200 µg/ml hydrocortisone and in a physiological concentration (0.4 µg/ml, normal conditions). The results of these experiments demonstrate the differential expression of 43 genes in the 500× (200 µg/ml) hydrocortisone construct as compared to the construct grown under normal conditions (0.4 µg/ml hydrocortisone). These preliminary experiments suggest that hydrocortisone at higher concentrations may exert its inhibitory effect on hyaluronate synthesis early in the glycolytic pathway, leading to HA biosynthesis by downregulation of phosphoglucomutase and glucose phosphate isomerase, possibly leading to depletion of the cellular pool of UDP-sugar precursors necessary for HA synthesis. Copyright © 2013 John Wiley & Sons, Ltd.

Evaluation of the atrophogenic potential of hydrocortisone 1% cream and pimecrolimus 1% cream in uninvolved forehead skin of patients with atopic dermatitis using optical coherence tomography

Topical corticosteroids are widely used to treat atopic dermatitis (AD), but their anti-inflammatory mode of action can be accompanied by several unwanted side effects including skin atrophy and telangiectasia. In this 8-week, investigator-blinded, intraindividual right-left comparison study with patients with mild-to-moderate AD, hydrocortisone 1% cream (HCT) was applied twice daily for 4 weeks on one side of forehead skin without clinical signs of AD and pimecrolimus 1% cream (PIM) on the other. Epidermal and dermal thickness were assessed by optical coherence tomography (OCT) and high-frequency ultrasound, respectively. Skin atrophy and telangiectasia were assessed by contact dermatoscopic photography (Dermaphot(®)). Treatment with HCT leads to a significant decrease in epidermal thickness after only 2 weeks of treatment, while the decrease in PIM-treated sites was less pronounced and was not statistically significant. By 4 weeks after the end of treatment, epidermal thickness returned to baseline values. No dermal thinning or development of telangiectasia could be observed by means of ultrasound or Dermaphot(®), respectively. In summary, this study indicates that a 2-week single course of topical treatment with a mildly potent steroid can cause transient epidermal thinning, an effect not seen in the PIM group. The slight decrease with PIM - although not significant - could be due to normalization of the increased skin thickness caused by a subclinical inflammation in AD. This study suggests that PIM may be safer for treatment of AD in sensitive skin areas like the face, especially when repeated application is required.

Test systems for the determination of glucocorticoid receptor ligand induced skin atrophy

Topical glucocorticoids are highly anti-inflammatory effective but limited by their side effect potential, with skin atrophy being the most prominent one. Thus, determining the atrophogenic potential of novel compounds targeting the glucocorticoid receptor is important. Significant progress in the understanding of glucocorticoid receptor mediated molecular action has been made providing the basis for novel glucocorticoid receptor ligands with a potentially superior effect/side effect profile. Such compounds, however, need to be tested. The present gold standard for the reliable prediction of glucocorticoid induced skin atrophy are still in vivo models, however, in vitro models may replace them to some extent in the future. Indeed, advances in technologies to determine the atrophogenic potential of compounds in vitro has been made recently and promising novel test models like the human full thickness skin models are emerging. Their full predictive value, however, needs to be further evaluated. Currently, a screening approach starting with a combination of several in vitro test systems followed by subsequent testing of the most promising compounds in rodent models is recommended prior entering clinical studies with selected development compounds.

Characterization of ZK 245186, a novel, selective glucocorticoid receptor agonist for the topical treatment of inflammatory skin diseases

BACKGROUND AND PURPOSE

Glucocorticoids are highly effective in the therapy of inflammatory diseases. Their value, however, is limited by side effects. The discovery of the molecular mechanisms of the glucocorticoid receptor and the recognition that activation and repression of gene expression could be addressed separately opened the possibility of achieving improved safety profiles by the identification of ligands that predominantly induce repression. Here we report on ZK 245186, a novel, non-steroidal, low-molecular-weight, glucocorticoid receptor-selective agonist for the topical treatment of inflammatory dermatoses.

EXPERIMENTAL APPROACH

Pharmacological properties of ZK 245186 and reference compounds were studied in terms of their potential anti-inflammatory and side effects in functional bioassays in vitro and in rodent models in vivo.

KEY RESULTS

Anti-inflammatory activity of ZK 245186 was demonstrated in in vitro assays for inhibition of cytokine secretion and T cell proliferation. In vivo, using irritant contact dermatitis and T cell-mediated contact allergy models in mice and rats, ZK 245186 showed anti-inflammatory efficacy after topical application similar to the classical glucocorticoids, mometasone furoate and methylprednisolone aceponate. ZK 245186, however, exhibits a better safety profile with regard to growth inhibition and induction of skin atrophy after long-term topical application, thymocyte apoptosis, hyperglycaemia and hepatic tyrosine aminotransferase activity.

CONCLUSIONS AND IMPLICATIONS

ZK 245186 is a potent anti-inflammatory compound with a lower potential for side effects, compared with classical glucocorticoids. It represents a promising drug candidate and is currently in clinical trials.

Hamamelis in children with skin disorders and skin injuries: results of an observational study

Published clinical experience with hamamelis ointment in children is limited. This observational study included children (age 27 days to 11 years) with minor skin injuries, diaper dermatitis, or localized inflammation of skin. The children received either hamamelis ointment or dexpanthenol ointment in groups at a 3-to-1 ratio. Baseline and post-treatment assessments compared the total scores of predefined signs and symptoms for each condition. Physicians and parents were asked for a global assessment of efficacy and tolerability of the respective treatments at the end of therapy. A total of 309 children were treated (hamamelis n = 231; dexpanthenol n = 78). The treatment groups were comparable regarding demographic data and baseline total scores of signs and symptoms. In all three diagnosis groups, the efficacy of hamamelis and dexpanthenol was shown by a statistically significant and clinically relevant decrease of total scores from baseline to endpoint (p < 0.0001 for each group, Wilcoxon signed-rank test). Overall, the results for the hamamelis and the dexpanthenol groups were similar. Descriptive advantages for the hamamelis group were observed for a number of parameters and diagnosis groups. Both treatments were well tolerated. Ratings of the tolerability of hamamelis were "excellent" or "good" in 99.1% (physicians) and 98.2% (parents) of cases, respectively. The corresponding ratings for dexpanthenol were 97.4 and 92.3%. In conclusion, hamamelis ointment is an effective and safe treatment for certain skin disorders in children up to the age of 11 years. The observed effects are similar to dexpanthenol.

Insight into the molecular mechanisms of glucocorticoid receptor action promotes identification of novel ligands with an improved therapeutic index

Glucocorticoids are highly effective in the therapy of inflammatory and autoimmune disorders. Their beneficial action is restricted because of their adverse effects upon prolonged usage. Topical glucocorticoids that act locally have been developed to significantly reduce systemic side effects. Nonetheless, undesirable cutaneous effects such as skin atrophy persist from the use of topical glucocorticoids. There is therefore a high medical need for drugs as effective as glucocorticoids but with a reduced side-effect profile. Glucocorticoids function by binding to and activating the glucocorticoid receptor that positively or negatively regulates the expression of specific genes. Several experiments suggest that the negative regulation of gene expression by the glucocorticoid receptor accounts for its anti-inflammatory action. This occurs through direct or indirect binding of the receptor to transcription factors such as activator protein-1, nuclear factor-kappaB or interferon regulatory factor-3 that are already bound to their regulatory sites. The positive action of the receptor occurs through homodimer binding of the receptor to discrete nucleotide sequences and this possibly contributes to some of the adverse effects of the hormone. Glucocorticoid receptor ligands that promote the negative regulatory action of the receptor with reduced positive regulatory function should therefore show improved therapeutic potential. A complete separation of the positive from the negative regulatory activities of the receptor has so far not been possible because of the interdependent nature of the two regulatory processes. Nevertheless, considerable improvement in the therapeutic action of glucocorticoid receptor ligands is being achieved through the use of key molecular targets for screening novel glucocorticoid receptor ligands.

Glucocorticoid therapy-induced skin atrophy

Glucocorticoids (GCs) are highly effective for the topical treatment of inflammatory skin diseases. Their long-term use, however, is often accompanied by severe and partially irreversible adverse effects, with atrophy being the most prominent limitation. Progress in the understanding of GC-mediated molecular action as well as some advances in technologies to determine the atrophogenic potential of compounds has been made recently. It is likely that the detailed mechanisms of GC-induced skin atrophy will be discovered and in vitro models for the reliable prediction of atrophy will be established in the foreseeable future. This knowledge will not only facilitate safety profiling of established drugs but will also foster further drug discovery by improving compound characterization processes. New insights into GC modes of action will guide optimization strategies aiming at novel GC receptor ligands with improved effect/side effect profile.

Blockade of experimental atopic dermatitis via topical NF-kappaB decoy oligonucleotide

Atopic dermatitis (AD) is a common chronic skin inflammatory disease. Long-term use of topical corticosteroids in skin inflammation poses risks of systemic and local side effects. The NF-kappaB transcription factor family plays a central role in the progression and maintenance of AD. This study explores the possibility of using topical NF-kappaB Decoy as a novel therapeutic alternative for targeting Th1/Th2-driven skin inflammation in experimental AD. A high-affinity, topical NF-kappaB Decoy developed for human efficacy demonstrates: (i) efficient NF-kappaB Decoy penetration in pig skin, (ii) NF-kappaB Decoy nuclear localization in keratinocytes and key immune cells, and (iii) potent "steroid-like" efficacy in a chronic dust-mite antigen skin inflammation treatment model. NF-kappaB Decoy exerts its anti-inflammatory action through the effective inhibition of essential regulators of inflammation and by induction of apoptosis of key immune cells. Unlike betamethasone valerate (BMV), long-term NF-kappaB Decoy treatment does not induce skin atrophy. Moreover, topical NF-kappaB Decoy, in contrast to BMV, restores compromised stratum corneum integrity and barrier function. Steroid withdrawal causes rapid rebound of inflammation, while the NF-kappaB Decoy therapeutic benefit was maintained for weeks. Thus, topical NF-kappaB Decoy provides a novel mechanism of reducing chronic skin inflammation with improved skin homeostasis and minimal side effects.

Hydrocortisone regulation of hyaluronan metabolism in human skin organ culture

We studied the influence of hydrocortisone (HC) on hyaluronan (HA) metabolism in explants of human skin, a model retaining normal three-dimensional architecture of dermal connective tissue and dynamic growth and stratification of epidermal keratinocytes. The synthesis of hyaluronan and proteoglycans (PGs), and DNA, were determined with 3H-glucosamine and 3H-thymidine labelings, respectively. The total content and histological distribution of hyaluronan was studied utilizing a biotinylated aggrecan-link protein complex. A low concentration of HC (10(-9) M) stimulated the incorporation of 3H-glucosamine into hyaluronan in epidermis by 23% and reduced the disappearance rate of hyaluronan by 25% in chase experiments, resulting in a 74% increase in total hyaluronan (per epidermal dry weight) after a 5-day culture in 10(-9) M HC. On the other hand, a high concentration of HC (10(-5) M) reduced both synthesis (-42%) and degradation (-46%) of epidermal hyaluronan during 24 h labeling and chase periods. The cumulative effect of a 5-day treatment was a 24% decrease of total epidermal hyaluronan. The high dose (10(-5) M) also reduced keratinocyte DNA synthesis and epidermal thickness. In dermis, only the high (10(-5) M) concentration of HC was effective, inhibiting the incorporation of 3H-glucosamine into hyaluronan by 28%. No significant influences on total hyaluronan content or the disappearance rate of hyaluronan in dermal tissue was found. All HC concentrations lacked significant effects on newly synthesized PGs in epidermal and dermal tissues, but reduced the labeled PGs diffusing into culture medium. A low physiological concentration of HC thus maintains active synthesis and high concentration of hyaluronan in epidermal tissue, while high pharmacological doses of HC slows hyaluronan turnover and reduces its content in epidermis, an effect correlated with enhanced terminal differentiation, reduced proliferation rate and reduced number of vital keratinocyte layers.

Decreased expression of collagen and fibronectin genes in striae distensae tissue

Striae distensae are characterized by a thinning of connective tissue stroma to produce linear, atrophic-appearing skin. Excessive adrenocortical activity, genetic factors and inherited defects of connective tissues, etc. are important causative factors in the formation of striae distensae, but the basic aetiology is not known. Total RNA was extracted from skin biopsies of five patients with striae distensae. The expression of genes coding for types I and III procollagen, elastin, fibronectin and beta-actin were studied and compared with those of four sex- and age-matched healthy individuals. The percentages of types I and III procollagen mRNA were 9.9 +/- 2.9% (mean +/- s.d.) and 10.6 +/- 1.6%, respectively, of the corresponding controls. The value for fibronectin mRNA in striae distensae was 7.3 +/- 1.8% of the control. The steady-state ratio fibronectin/type I procollagen mRNAs was 0.12 +/- 0.01 in striae distensae and 0.18 +/- 0.01 in the control. These observations suggest that expression of collagens, elastin and fibronectin genes are apparently decreased, and that there is a marked alteration of fibroblast metabolism, in striae distensae.

Serum markers of collagen synthesis and degradation in skin diseases. Altered levels in diseases with systemic manifestation and during systemic glucocorticoid treatment

Serum concentrations of the markers of collagen synthesis and degradation, collagen I propeptide (PICP), collagen III propeptide (PIIINP) and the cross-linked telopeptide of type I collagen (ICTP) were measured in young male dermatological patients and in control subjects. No significant differences were noted between patients suffering from atopic eczema (n = 24), other eczemas (n = 11), acne (n = 8), psoriasis (n = 7) or tinea (n = 9) and the control subjects (n = 24). In the total study population representing patients with common skin diseases and control subjects there was a significant correlation between the serum concentrations of PICP and PIIINP and between the concentrations of PICP and ICTP. This suggests that synthesis of type I and III collagens in vivo is coordinated and that the degradation and synthesis of type I collagen is balanced. These markers were also measured in older patients suffering from psoriasis, eczema and various connective tissue diseases. It was noted that the degree of skin involvement in these diseases was not related to the serum concentrations of the markers of collagen metabolism. The highest levels of PICP and PIIINP were observed in a patient with systemic mastocytosis (PICP 309 micrograms/l and PIIINP 8.0 micrograms/l). Increased levels of PIIINP were also found in patients with a high alcohol consumption. We have previously demonstrated that systemic glucocorticoids reduce collagen propeptide levels in serum. In the present study we also proved that systemic glucocorticoids have no effect on collagen degradation.(ABSTRACT TRUNCATED AT 250 WORDS)

New aspects of the mechanism of corticosteroid-induced dermal atrophy

Glucocorticoids are effective for the treatment of various inflammatory skin diseases, but their long-term use may lead to serious side-effects such as osteoporosis and skin atrophy. The incidence of skin atrophy following application of potent corticosteroids is especially high among children and the elderly. During recent years the effects of glucocorticoids on connective tissue have been elucidated, and it is evident that skin atrophy is mostly due to a decrease in collagen synthesis. Since collagen is the most abundant protein in the skin, the inhibition of its synthesis leads to atrophy. This review discusses the molecular mechanisms of glucocorticosteroid-induced skin atrophy and therapeutic possibilities.

Comparison of the effects of dexamethasone and 13-cis-retinoic acid on connective tissue biosynthesis in human skin fibroblasts

The effects of glucocorticoids and retinoids on connective tissue biosynthesis were studied in cultured human skin fibroblasts (HSFs). More specifically attention was paid to the effects of dexamethasone and 13-cis-retinoic acid (RA) on total protein and collagen synthesis and on collagen and fibronectin mRNA levels. The results indicated that dexamethasone reduced the relative collagen synthesis and collagen mRNA levels in HSFs and increased the total incorporation of proline into proteins, the latter effect being due to increased activity in the intracellular proline pool. 13-cis-RA did not affect collagen synthesis at the concentration studied (10(-7) M) but it did reduce the corresponding mRNA levels. Simultaneous addition of both dexamethasone and 13-cis-RA or etretinate resulted in the largest decrease in type I and type III procollagen mRNA levels, indicating that retinoids do not oppose the effect of glucocorticoids on collagen synthesis in cultured HSFs. For comparison the effects of dexamethasone and 13-cis-RA on the mRNA levels of another extracellular matrix component, fibronectin, and of a constitutive enzyme, glyceraldehyde-3-phosphate dehydrogenase, were also studied. The results indicated, that dexamethasone treatment did not alter fibronectin mRNA levels in HSFs, while 13-cis-RA did so to a marked extent. Both dexamethasone and 13-cis-RA also reduced the mRNA level of glyceraldehyde-3-phosphate dehydrogenase, indicating that glucocorticoids and retinoids have both similar and different effects on gene expression in HSF.

Extracellular matrix of the skin: 50 years of progress

The extracellular connective tissue matrix of the skin is a complex aggregate of distinct collagenous and non-collagenous components. Optimal quantities and delicate interactions of these components are necessary to maintain normal physiologic properties of skin. This overview summarizes the progress made in understanding the normal biology and biochemistry of the extracellular matrix, and will highlight cutaneous diseases with underlying molecular defects in the structure and expression of extracellular matrix components.

Modulation of collagen metabolism by glucocorticoids. Receptor-mediated effects of dexamethasone on collagen biosynthesis in chick embryo fibroblasts and chondrocytes

The steroid modulation of collagen metabolism was studied by injecting chick embryos with dexamethasone in vivo, and collagen synthesis was subsequently assayed by pulse-labeling the tissue with [14C]proline in vitro. The synthesis of [14C]hydroxyproline in tendons and sterna from chick embryos treated with dexamethasone was markedly reduced as compared with untreated controls. The inhibition of [3H]hydroxyproline synthesis was accompanied by a similar reduction in type I and II procollagen mRNA levels, as detected by Northern blot and dot blot hybridizations with chick pro alpha 1(I), pro alpha 2(I) and pro alpha 1(II) sequence specific cDNAs. The reduction in type II procollagen mRNA level was shown to be dose dependent. Control experiments indicated that the post-translational hydroxylation of prolyl residues was only slightly decreased in dexamethasone treated animals, and that the specific activity of the intracellular free proline pool and the intracellular degradation of collagen were unchanged. To address the mechanisms of the inhibition of collagen biosynthesis, specific binding of dexamethasone to glucocorticoid receptors in chick embryo tendon and cartilage cells was studied in a whole cell assay using [3H]dexamethasone as the ligand. Matrix-free tendon and cartilage cells had approximately 19,000 and 15,000 receptor sites per cell, respectively, and the binding affinities (Kd) for dexamethasone in tendon and cartilage cells were 2.9 x 10(-9) and 2.3 x 10(-9) M. Comparable values were obtained using a cytosol binding assay. The nuclear binding of dexamethasone in tendon and cartilage cells were similar. The results suggest that the dexamethasone-induced inhibition of collagen production is primarily due to decreased levels of functional procollagen mRNA, possibly resulting from receptor-mediated inhibition of the gene expression on the transcriptional level.

Age differences in the effect of hydrocortisone on the synthesis of insoluble elastin in aortic tissue of growing chicks

Glucocorticoids have been shown by others to increase the synthesis of elastin both in aortic tissue of embryo chicks and in cells derived from fetal ligamentum nuchae. This report describes the effects of hydrocortisone on the production of elastin in aortic tissue of developing chick embryos and chicks. While the effect of hydrocortisone on elastin synthesis is stimulatory in the 14 day chick embryo and the day-old chick, the same dose of this glucocorticoid has no effect on elastin production in the 7 day old chick and significantly inhibits synthesis of elastin in the 14 day old chick. These age-related alterations in elastin production in response to hydrocortisone cannot be attributed to an effect of the steroid on the pool size of the radioactively labelled amino acid used to measure elastin synthesis.

[Physiopathologic bases of the treatment of systemic scleroderma]

Numerous drugs have been suggested for the treatment of systemic scleroderma. They may be studied and classified according to their site of action on the chain of events that leads from vascular abnormalities to sclerosis of the skin. Thus, proline analogues, colchicine, lathyrogenic agents, D-penicillamine, coagulation factor XIII and oestrogens are thought to act on collagens and their metabolism. Ketanserin has been suggested by the discovery of tryptophan abnormalities. Corticosteroids exert an inhibitory effect on fibroblasts. The use of calcium antagonists, angiotensin-converting enzyme inhibitors, prostacyclin and anti-platelets rests on the presence of vascular abnormalities. The purpose of treatments with immunosuppressive drugs or plasma exchanges is to act on possible lymphocytic and/or macropageal factors.

Plantar fibromatosis responds to intralesional steroids

A case of plantar fibromatosis that responded to five monthly intralesional steroid injections is reported. Improvement was noted after 3 to 4 months of therapy. Intralesional steroid injections may represent an alternative to surgery in patients with plantar fibromatosis or Dupuytren's contractures.

Inhibition of collagen accumulation in fibrotic processes: review of pharmacologic agents and new approaches with amino acids and their analogues

Accumulation of collagen is the major pathologic feature in a variety of fibrotic processes, including dermal fibrosis in progressive systemic sclerosis, morphea, familial cutaneous collagenoma, connective tissue nevi of the collagen type and in keloids. Recent advances in the biochemistry of collagen have allowed us to define specific levels of collagen biosynthesis and degradation at which a pharmacologic intervention can lead to reduced collagen deposition. In this review, we are discussing the mechanisms of action by some of the therapeutic agents currently in use. We further present some new developments involving amino acids and their analogues which could potentially provide us with novel means to reduce the excessive accumulation of collagen in dermal fibrotic processes.