Melasma is defined as the patchy darkening of skin in sun exposed areas, typically on the face. The cheekbones, cheeks, and forehead are most commonly affected. 90% of cases occur in women and it is thought to be related to hormonal activity, especially progesterone, but the exact mechanism is not known. Melasma is most common in medium-pigment skin, such as in Asians and Hispanics.
The patches of increased pigment begin very gradually but can become quite noticeable and bothersome. The “mask of pregnancy” is a manifestation of melasma. Starting oral contraceptives can also bring on melasma.
Melasma is challenging to treat. First and most importantly, the stimulus for the melasma must be addressed. Strict sun avoidance is a requirement. Even visible light can stimulate melasma lesions, so sunblocks are not adequate by themselves, since they only screen out UV light. Second, if oral contraceptives are being used, alternatives should be explored.
The mainstay of melasma treatment is topical. Hydroquinone is the foremost bleaching cream that inhibits the enzyme in the skin that makes melanin. There are alternative bleaching agents, such as kojic acid, but hydroquinone is the best-studied and gives the best results. Retinoic acid is also helpful by speeding up skin cell turnover. When hydroquinone, retinoic acid and a topical steroid are used as a triple combination together, the best results occur. Even so, results take months to achieve, and sun avoidance must be maintained .
Lasers and chemical peels are an option to speed the improvement of melasma. Chemical peels remove the overlying layers of pigmented epidermis and so are helpful. However, they will not penetrate into the deeper layers of skin pigment. Fractionated laser, such as Fraxel, can be helpful but there is a small risk of reactive hyperpigmentation. Q-switched Nd:YAG is also helpful and works by a different mechanism, similar to laser tattoo removal. However, all these methods are adjuncts to topical treatment and will not achieve good results without pretreatment with topicals.

Botox offers amazing benefits for facial anti-aging.  Many people are familiar with its mechanism of action in general terms, that it works by freezing muscles of facial expression that cause wrinkles. However, there are some subtle caveats that not everyone appreciates.
The best candidates for wrinkle treatment with Botox or Dysport are those patients who have wrinkles during muscle activity but otherwise do not have severe wrinkles at rest.  This can be tested by relaxing the relevant facial muscles to see what effect that has on those wrinkles.  If the wrinkles are primarily due to the effect of poor skin tone, loss of underlying tissue or gravity, then Botox is less likely to yield any benefit.  In such cases, a dermal filler, such as Juvederm or Radiesse, is more likely to help.

One must also be aware of the effect of relaxing a facial muscle on one’s facial expression.  Although wrinkles may go away, expression may be changed.  For example, some people have excess skin laxity in their foreheads and keep their forehead muscles working constantly to keep their eyebrows from covering their eyes.  If the forehead were weakened in that area, then the eyebrows could fall and cause vision to be obstructed.  Only a brow lift would be helpful in such a case.

Skin vitality is also important.  Wrinkles formed from dynamic muscle action don’t disappear immediately.  The skin remodels itself to smooth out wrinkles over time, but this action depends on the health and age of the skin.  For instance, one would expect that a 35 year old with forehead wrinkles would probably see more improvement with Botox than a 65 year old.

When getting Botox or Dysport for the first time, it is very important to go over the cosmetic goals, as well as the risks and benefits.  Realistic expectations are key to being satisfied with this procedure.