Citric acid increases viable epidermal thickness and glycosaminoglycan content of sun-damaged skin.

BACKGROUND: Recently, there has been an exponential increase in the use of alpha-hydroxy acids in dermatologic practice. Their inclusion in a myriad of cosmetic preparations underscores their popularity. Among the clinical effects of alpha-hydroxy acids are their ability to prevent the atropy resulting from potent topical corticosteroids, improve the appearance of photoaged skin, and correct disorders of keratinization. Despite this range of desirable effects, very little is known about the specific changes produced by various alpha-hydroxy acid preparations in the epidermis and dermal extracellular matrix. Previous work by others has demonstrated the ability of another alpha-hydroxy acid to increase viable epidermal thickness, and dermal glycosaminoglycans. OBJECTIVE: In this study, we examined the effect of 20% citric acid lotion, as compared with vehicle alone, on skin thickness, viable epidermal thickness, and dermal glycosaminoglycan content. Biopsy samples were harvested after 3 months of treatment. RESULTS: Image analysis of biopsy sections revealed increases in viable epidermal thickness and dermal glycosaminoglycans in treated skin. CONCLUSIONS: Topical citric acid produces changes similar to those observed in response to glycolic acid, ammonium lactate, and retinoic acid including increases in epidermal and dermal glycosaminoglycans and viable epidermal thickness. Further studies of citric acid and other alpha-hydroxy acids are warranted to clarify their clinical effects and mechanisms of action.

Increased factor XIIIa transglutaminase expression in dermal dendrocytes after treatment with alpha-hydroxy acids: potential physiologic significance.

BACKGROUND: Topical alpha-hydroxy acids (AHAs) have been shown to improve photoaging in human skin. OBJECTIVE: We studied factor XIIIa transglutaminase expression in dermal dendrocytes (DDs) and mast cell degranulation after treatment of the skin with AHAs. METHODS: Skin biopsy specimens obtained from patients after 4 to 8 months of treatment with lotions containing 25% AHAs were evaluated for factor XIIIa transglutaminase expression with immunoperoxidase and electron microscopy. Immunoperoxidase-stained sections were studied by means of semiquantitative methods and image analysis. Mast cell degranulation was studied by image analysis. RESULTS: Increased factor XIIIa transglutaminase expression was seen after treatment with AHAs. All treated sites had increased scores compared with control sites by semiquantitative methods. Seventy-five percent of treated sites showed an increased mean area over control sites of factor XIIIa transglutaminase positivity with image analysis. These results correlated with an increased level of mast cell degranulation in treated sites and with activation of DDs as seen by electron microscopy. CONCLUSION: Treatment of the skin with AHAs leads to mast cell degranulation and increased expression of factor XIIIa transglutaminase by activated DDs. Mast cell degranulation may lead to activation of DDs and increased factor XIIIa transglutaminase expression, via the action of tumor necrosis factor-alpha. We speculate that clinical and histologic improvement in photoaged skin after treatment with AHAs may be somehow related to this process.

Effects of alpha-hydroxy acids on photoaged skin: a pilot clinical, histologic, and ultrastructural study.

BACKGROUND: alpha-Hydroxy acids (AHAs) have been reported to improve aging skin. The mechanisms of action of AHAs on epidermal and dermal compartments need clarification. OBJECTIVE: Our purpose was to determine the effects of AHAs on photoaged human skin by clinical and microanalytic means. METHODS: Patients applied a lotion containing 25% glycolic, lactic, or citric acid to one forearm and a placebo lotion to the opposite forearm for an average of 6 months. Thickness of forearm skin was measured throughout the study. Biopsy specimens from both forearms were processed for analysis at the end of the study. RESULTS: Treatment with AHAs caused an approximate 25% increase in skin thickness. The epidermis was thicker and papillary dermal changes included increased thickness, increased acid mucopolysaccharides, improved quality of elastic fibers, and increased density of collagen. No inflammation was evident. CONCLUSION: Treatment with AHAs produced significant reversal of epidermal and dermal markers of photoaging.

Topical tretinoin (retinoic acid) improves melasma. A vehicle-controlled, clinical trial.

Melasma is a common disorder of cutaneous hyperpigmentation predominantly affecting the faces of women. Little is known about the aetiology of melasma, and treatment is frequently disappointing. Topical tretinoin is of benefit in treating other forms of hyperpigmentation, for example liver spots, and we therefore investigated its effectiveness in melasma. Thirty-eight women completed a randomized, vehicle-controlled study, in which they applied 0.1% tretinoin (n = 19) or vehicle cream (n = 19) once daily to the face for 40 weeks. At the end of treatment 13 (68%) of 19 tretinoin-treated patients were clinically rated as improved or much improved, compared with 1 (5%) of 19 in the vehicle group (P = 0.0006). Significant improvement first occurred after 24 weeks of tretinoin treatment. Colorimetry (an objective measure of skin colour) demonstrated a 0.9 unit lightening of tretinoin-treated melasma and a 0.3 unit darkening with vehicle (P = 0.01); these results correlated with clinical lightening (r = 0.55, P = 0.0005). Histologically, epidermal pigment was reduced 36% following tretinoin treatment, compared with a 50% increase with vehicle (P = 0.002). Reduction in epidermal pigment also correlated with clinical lightening (r = -0.41, P = 0.01). Moderate cutaneous side-effects of erythema and desquamation occurred in 88% of tretinoin-treated and 29% of vehicle-treated patients. Topical 0.1% tretinoin produces significant clinical improvement of melasma, mainly due to reduction in epidermal pigment, but improvement is slow.

Dilated pore nevus. A histologic variant of nevus comedonicus.

Histology of a nevus comedonicus showed aggregates of dilated follicular cysts reminiscent of dilated pore of Winer. This finding has not been previously reported. We propose the term dilated pore nevus for this lesion, which we conceive to be a histologic variant of nevus comedonicus, similar to porokeratotic eccrine ostial and dermal duct nevus.

Surgical anatomy of the nail unit.

A gross anatomic exploration of the nail unit was performed. The characteristic gross components of the nail unit and its relationship to the digital anatomy are described and presented in detail. Each segment of the nail unit is illustrated both photographically and with artistic illustration. It is our intention that through a simple gross dissection the nail structural unit may be better understood.

Plaque-type intertriginous cutaneous calcification.

Cutaneous calcification is classified into four types: dystrophic, idiopathic, tumoral, and metastatic. We present a patient with systemic lupus erythematosus undergoing hemodialysis who noted large plaque-like cutaneous calcifications in the axillae and groin. Some plaques occurred in association with striae related to prior corticosteroid therapy for the patient's underlying systemic disease. This case is unusual because of the clinical presentation, its demonstration of both dystrophic and metastatic types of calcification, and histologic calcification of elastic fibers simulating pseudoxanthoma elasticum.

Topical tretinoin (retinoic acid) treatment for liver spots associated with photodamage.

BACKGROUND: The hyperpigmented lesions commonly called liver spots distress patients, in part because such lesions are associated with aging. We investigated their treatment with topical 0.1 percent tretinoin (retinoic acid). METHODS: Fifty-eight patients completed a 10-month randomized, double-blind study in which they applied either 0.1 percent tretinoin (n = 28) or vehicle (n = 30) cream daily to the face, upper extremities, or both. Fifteen patients who responded well were than randomly assigned to continue tretinoin therapy or use vehicle alone for six more months. Patients were evaluated by physical examination every month and by analysis of biopsy specimens of lesions obtained at base line and at the end of the 10-month trial. RESULTS: After one month of treatment the patients treated with tretinoin had significant lightening of hyperpigmented lesions as compared with the patients who received vehicle (P less than 0.002). After 10 months, 20 (83 percent) of the 24 patients with facial lesions who were treated with tretinoin had lightening of these lesions, as compared with 8 (29 percent) of the 28 patients with facial lesions who received vehicle. The results for lesions of the upper extremities were similar. As compared with vehicle, tretinoin caused a significant decrease in the degree of epidermal pigmentation and increases in the degree of compaction of stratum corneum, thickness of the granular cell layer, and epidermal thickness. Reductions in epidermal pigmentation evident on histologic analysis were significantly correlated with the degree of clinical lightening of lesions (r = -0.53, P less than 0.0001). During the 6-month follow-up study, specifically identified lesions that had disappeared during the first 10 months of tretinoin treatment did not return in any patient, and six of seven patients who continued to use tretinoin had further improvement. CONCLUSIONS: Topical 0.1 percent tretinoin significantly improves both clinical and microscopical manifestations of liver spots; these lesions do not return for at least six months after therapy is discontinued.