Laser and light based treatments of acne.

Medical treatments for acne vulgaris include a variety of topical and oral medications. Poor compliance, lack of durable remission, and potential side effects are common drawbacks to these treatments. Therefore, there is a growing demand for a fast, safe, and side-effect-free novel therapy. Acne often improves after exposure to sunlight, and this has led to the development of laser and other light therapies resulting in the overall ease of treatment, with minimal adverse effects. A variety of light and laser devices has been used for the treatment of acne, including the potassium titanyl phosphate laser, the 585- and 595-nm pulsed dye lasers, the 1450-nm diode laser, radiofrequency devices, intense pulsed light sources, and photodynamic therapy using 5-aminolevulinic acid and indocyanine green. These devices are thought to target the underlying pathogenic factors such as propionibacterium acnes colonization, increased sebaceous gland activity, and the cutaneous inflammatory response. In this article, we review the current status of light- and laser-based treatment of acne.

Antiphospholipid syndrome in dermatology: An update.

Antiphospholipid syndrome (APS) is characterized by the presence of antiphospholipid antibodies, recurrent thrombosis, and fetal loss. Antiphospholipid antibodies are a family of autoantibodies that recognize various combinations of phospholipids, phospholipid-binding proteins, or both. APS can occur in the absence of underlying or associated disease (primary APS) or in combination with other diseases (secondary APS). The exact pathogenic mechanism by which these antibodies cause thrombosis is not known; however, several hypotheses, such as activation of platelet and endothelial cells and interference with the coagulation system, have been proposed. Diagnosis is based on the presence of at least one clinical and laboratory criterion each, according to International Consensus Statement on preliminary classification criteria. However, APS can be diagnosed in individuals even in the absence of some of the classification criteria. Clinical manifestations involve different organs and systems such as the blood vessels, central nervous system, skin, kidneys, gastrointestinal tract, heart, and placenta. The unifying mechanism of all these manifestations is thrombosis, either arterial or venous. Skin manifestations are varied and although not included in the diagnostic criteria, may be the presenting feature of this syndrome. Therefore all dermatologists should investigate the possibility of APS when cutaneous findings are related to venous or arterial thrombosis. The risk of thrombosis cannot be predicted, and therefore treatment is not initiated until a thrombotic event occurs. Indefinite anticoagulation is prescribed once a thrombotic event occurs. Prognosis depends on the severity of the clinical manifestations and so, knowledge of the presentation of this disease is important for early detection and prompt treatment to prevent life-threatening consequences of this catastrophic disease process.

Histamine 2 blocker potentiates the effects of histamine 1 blocker in suppressing histamine-induced wheal.

BACKGROUND: Histamine is responsible for the wheal and flare reaction in various allergic conditions. Classical antihistamines are the drugs which block the H 1 receptors and are widely used in various allergic conditions, whereas H 2 blockers are mainly used for acid peptic disease. Although H 1 receptor-mediated actions of histamine are primarily responsible for vasodilatation, vasopermeability, and itching, it has been observed that combined blocking of both H1 and H2 receptors may provide better relief. AIM: To compare the efficacy of levocetirizine (H1 blocker) versus levocetirizine and ranitidine (H2 blocker) in suppressing histamine-induced wheal. METHODS: Fifteen volunteers were given a single dose of levocetirizine 5 mg on day 1 and a single dose of levocetirizine 5 mg with ranitidine 150 mg twice a day on day 7. A pretest was performed by intradermal histamine prick test. After administration of the drugs, the prick test was repeated at 1 hour, 2, 3, 6, and 24 hours, and the size of the wheal measured and statistically analyzed. RESULTS: At 1 hour, there was no statistically significant difference in the wheal size between levocetirizine alone and the combination of levocetirizine and ranitidine. Levocetirizine with ranitidine resulted in statistically significant reduction of wheal size at 2, 3, 6, and 24 hours when compared with levocetirizine alone. CONCLUSION: H2 blocker potentiates the effects of an H1 blocker in suppressing histamine-induced wheal.

Comparative efficacy of levocetirizine, desloratidine and fexofenadine by histamine wheal suppression test.

BACKGROUND: Histamine is the major mediator of allergic reactions. Newer H1 antihistaminics like levocetirizine, fexofenadine, and desloratadine are used in the treatment of seasonal and perennial allergic rhinitis and urticaria. The ability to block the cutaneous response to intradermal histamine is used to evaluate the potential of antihistamines. AIMS: To compare the potency, onset, and duration of action of the commonly used antihistamines-levocetirizine, fexofenadine, and desloratadine. METHODS: Thirty volunteers were given three single doses of levocetirizine, fexofenadine and desloratadine at weekly intervals. A pretest was performed by using the intradermal histamine prick test. After administration of the drugs, the intradermal test was repeated at (1/2), 1, 2, 3, 6 and 24 h, and the sizes of the wheal were measured. The mean values were taken and were compared by using Levene's t-test. RESULTS: At 30 min, fexofenadine showed a statistically significant suppression of wheal size compared to levocetirizine and desloratadine. Two and three hours after administration, levocetirizine and fexofenadine showed statistically significant inhibition of wheal size while only levocetirizine had this effect after six hours when compared to desloratadine. Desloratadine showed greater inhibition of wheal size at the end of 24 h when compared to levocetirizine and fexofenadine but this was not statistically significant. CONCLUSIONS: Fexofenadine had the earliest onset of action while levocetirizine showed maximum inhibition of wheal response after three and six hours.

Photoprotection.

The deleterious effect of ultraviolet radiation on humans has increased the need for photoprotection. Sunscreens are widely used as photo protective agents. They are divided into chemical sunscreens which absorb high-energy ultraviolet rays and physical blockers which reflect or scatter light. Effectiveness of sunscreens depends upon sun protection factor and its substantivity. Clothing is also important for sun protection and its effectiveness is measured by Ultraviolet Protection Factor. There are many other agents with photo protective properties, which range from antioxidants to plant extracts to DNA repair enzymes. Usage of wide brimmed hats and sunglasses, avoidance of solar exposure at times of peak intensity, use of cover-up garments and sunscreen lotions are effective for photo protection of the skin.

Study of histamine wheal suppression by dexamethasone with and without iontophoresis.

BACKGROUND: Iontophoresis increases the penetration of drugs into the skin by electric current. The ability of topical steroids to reduce the size of the histamine wheal was used to assess the efficacy of topical dexamethasone delivered with and without iontophoresis. AIM: To determine the wheal suppressing ability of dexamethasone delivered with and without iontophoresis. METHODS: A template with three squares of 3x3 cm was placed on both forearms of 20 volunteers and the edges marked. A gauze piece soaked in 2 ml of dexamethasone solution was placed on the flexor aspect of the left forearm and the electrode, an aluminum foil was placed on it and connected to the negative pole (since dexamethasone is negatively charged). An electric current was passed for 15 minutes. Similarly, on the right forearm, a dexamethasone soaked gauze piece was placed without iontophoresis. Histamine wheal suppression was assessed at the end of 30 min, 1 hr and 2 hrs, on both sides. Statistical analysis was done using an independent t-test. RESULTS: There was a statistically significant difference in wheal suppression at 30 min (p=0.006) on the left hand where iontophoresis was used. CONCLUSION: Our experiment showed that topical dexamethasone with iontophoresis has the maximum effect at the end of 30 minutes and is more effective than dexamethasone without iontophoresis.

Iontophoresis in dermatology.

Iontophoresis is the process of increasing the penetration of drugs into the skin by application of an electric current. The drug is applied under an electrode of the same charge as the drug, and a return electrode opposite in charge to the drug is placed at a neutral site on the body surface. Electrical energy assists the movement of ions across the skin using the principle "like charges repel each other and opposite charges attract". In this article, we discuss the mechanism, principles, factors influencing iontophoresis and its application for various dermatological conditions.

Half an hour versus three hour contact of topical steroid (clobetasol propionate).

BACKGROUND: Steroids when left on the skin for longer duration may contribute to the side effects without any additional clinical benefit. The relationship between the duration of topical steroid contact with the skin and its effectiveness has not been established. The ability of the topical steroids to inhibit the size of histamine induced wheal was used to assess their relative efficacy. AIM: To determine whether half an hour contact and three hour contact of a topical steroid, clobetasol propionate, is equally effective in inhibiting the size of the histamine induced wheal. METHODS: On 30 volunteers, 4 squares were marked on flexor aspect of both forearms using a template. One fingertip unit of clobetasol propionate 0.05% was applied on all the areas. Half an hour later all areas of left forearm and last square of right forearm were wiped. Prick testing was done with histamine and size of wheal recorded after 15 minutes. Similarly steroid was wiped from the 1st, 2nd, 3rd square after 1 hr, 2 hr and 3 hrs on right forearm and the corresponding areas prick tested on both forearms. RESULTS: There was statistically significant wheal suppression at the end of 2 hrs and 3 hrs as compared to half an hour. CONCLUSION: We conclude that half an hour application of clobetasol propionate is ineffective and that it is effective only after two hours of contact and hence short contact of half an hour will be less effective than relatively prolonged contact of 2 hours.

Meshed split skin graft for extensive vitiligo.

A 30 year old female presented with generalized stable vitiligo involving large areas of the body. Since large areas were to be treated it was decided to do meshed split skin graft. A phototoxic blister over recipient site was induced by applying 8 MOP solution followed by exposure to UVA. The split skin graft was harvested from donor area by Padgett dermatome which was meshed by an ampligreffe to increase the size of the graft by 4 times. Significant pigmentation of the depigmented skin was seen after 5 months. This procedure helps to cover large recipient areas, when pigmented donor skin is limited with minimal risk of scarring. Phototoxic blister enables easy separation of epidermis thus saving time required for dermabrasion from recipient site.