By interfering with the production of melanin in the epidermis, hydroquinone leads to less hyperpigmentation as darkened skin cells are naturally shed over time. Improvement in skin hyperpigmentation is typically seen within six months when used twice daily. Hydroquinone is ineffective for hyperpigmentation affecting deeper layers of skin such as the dermis. The use of a sunscreen with SPF 15 or higher in the morning with reapplication every two hours is recommended when using hydroquinone. Its application only to affected areas lowers the risk of lightening the color of normal skin but can lead to a temporary ring of lightened skin around the hyperpigmented area. Hydroquinone is generally well-tolerated; side effects are typically mild (e.g., skin irritation) and occur with the use of a higher than the recommended 4% concentration. Most preparations contain the preservative sodium metabisulfite, which has been linked to rare cases of allergic reactions, including anaphylaxis and severe asthma exacerbations in susceptible people. In extremely rare cases, the frequent and improper application of high-dose hydroquinone has been associated with a systemic condition known as exogenous ochronosis (skin discoloration and connective tissue damage from the accumulation of homogentisic acid). Combination therapy
Combination therapy—using medications of different classes together, each with a different mechanism of action—has been demonstrated to be a more effective approach to acne treatment than monotherapy. The use of topical benzoyl peroxide and antibiotics together is more effective than antibiotics alone. Similarly, using a topical retinoid with an antibiotic clears acne lesions faster than the use of antibiotics alone.
Langer–Giedion syndrome (LGS) is a very uncommon autosomal dominant genetic disorder caused by a deletion of a small section of material on chromosome 8. It is named after the two doctors who undertook the main research into the condition in the 1960s. Diagnosis is usually made at birth or in early childhood. Signs and symptoms
The features associated with this condition include: mild to moderate learning difficulties, short stature, unique facial features, small head and skeletal abnormalities including bony growths projecting from the surfaces of bones. Craniofacial
Individuals with Langer–Giedion syndrome may display characteristic craniofacial abnormalities. These include a long prominent philtrum, a thin upper lip,  wide spaced eyes, a bulbous nasal tip, a broad nasal bridge, wide nostrils, micrognathia, retrognathia, deep set eyes and large ears. The head itself is often  unusually small in comparison to that of unaffected individuals of the same age and sex. Dental abnormalities, such as supernumerary central incisors and the absence of some teeth, may occur

Muscoskeletal
Langer–Giedion syndrome causes cone shaped epiphyses of the phalanges of the hands and short fingers and toes. The fifth fingers are sometimes  bent. Skeletal abnormalities not affecting the hands and feet may also occur. These include winged scapula, thin ribs and scoliosis. In addition, individuals with Langer–Giedion syndrome may develop hip problems similar to those seen in Legg–Calvé–Perthes disease such as progressive degeneration of the head of the thigh bone.As affected individuals age they often develop benign boney growths called exostoses which project off the surfaces of the bones.