新人999脸部黄褐斑如何治疗配图，仅供参考
TOPICAL TREATMENTHydroquinone (HQ). HQ is a depigmenting agent that works by inhibiting melanin synthesis.? Its use as monotherapy and in triple combination cream (hydroquinone,tretinoin,and corticosteroid) remain the most well-studied and effective treatments. Numerous studies have shown that once-daily triple combination cream has good efficacy. After eight weeks of treatment,one study showed that 29 percent of patients had complete clearance of melasma. The same study also showed that 77 percent of patients were clear or almost clear at the end of eight weeks. Patients should be counseled on potential adverse side effects of HQ,the most common of which is irritation. Other adverse side effects include allergic contact dermatitis,erythema,inflammation,xeroderma and stinging. It should be noted that adverse reactions to HQ are often related to its strength and the length of treatment. A rare complication of HQ use is ochronosis,which presents as a blue-black or gray-blue macular pigmentation. It is most often associated with high concentrations of HQ used over long periods of time. Patients should be also counseled on the anticipated duration of treatment with HQ. Improvement often begins 5 to 7 weeks after treatment initiation and treatment should be continued for a minimum of three months.
Azelaic acid (AzA). AzA is a naturally occurring acid that has antityrosinase activity. It selectively targets abnormal melanocytes and does not depigment normally pigmented skin. One study comparing AzA 20% to HQ 4% twice daily for eight weeks showed that those treated with AzA 20% had statistically better Melasma Area Severity Index (MASI) scores than those treated with HQ 4%.
Cysteamine. Cysteamine is an aminothiol that has tyrosinase inhibition properties. It is also known to be a potent depigmenting agent. One study (N=20) comparing cysteamine to HQ in patients with melasma showed no statistically significant difference in modified MASI (mMASI) scores between the two groups at Week 16. It should be noted that side effects,although mild and reversible,were more common in the cysteamine group. Another study (N=40) comparing cysteamine cream once daily to placebo for 16 weeks in patients with melasma showed significantly lower MASI scores in the cysteamine group. Further studies are needed with larger sample sizes and long-term follow-up to support these findings.","department":"
