If you have recently noticed a discolouration of your skin, it could be caused by the medications you take or the foods you typically eat.
Drug-Induced Skin Pigmentation
Medication causes 10 to 20% of hyperpigmentation cases, with the main culprits being NSAIDs, phenytoin, antimalarials, antipsychotics, heavy metals, cytotoxics, tetracylines, and amiodarone. There are three classifications: hyperpigmentation (melanosis), which causes patches of skin to become darker in colour, hypopigmentation (leukoderma), which refers to the loss of skin color due to a depletion of melanin or an amino acid decrease, and dyspigmentation, which is an occurrence of unusual skin colour. Different drugs present different types of skin pigmentation and so the condition can take many forms; for example, psychotropic drugs can cause areas of the skin to turn blue-grey in colour, as can gold. In some cases, skin pigmentation only occurs in areas that are exposed to the sun, as seen in drugs like antimalarials, amiodarone, and psychotropic drugs. For a detailed list of the skin pigmentation effects of various substances, click this link and examine Table I on page 255.
Treatment for such occurrences is usually quite limited and consists of either advising the patient to avoid the sun, as drug-induced skin pigmentation is exacerbated or even caused by exposure to the sun or ceasing use of the offending drug. Luckily, drug-induced skin pigmentation is usually temporary; once someone has stopped taking the medication, skin almost always returns to its original colour. If it does not, laser treatment has been shown to be highly effective in treating skin pigmentation issues.
Food-Induced Skin Pigmentation
One cause of food-induced skin pigmentation is the chemical psoralen, which increases the risk of age spots and makes the skin more sensitive to UV rays. Psoralen is found in foods like the common fig, parsley, parsnips, limes, and celery. However, for skin pigmentation to occurs, the food must come into contact with the skin. In other words, simply eating foods that contain psoralen will not cause hyperpigmentation. Incidentally, psoralen’s skin-darkening effect makes it one of the most common treatments for hypopigmentation, like that seen in sufferers of vitiligo, psoriasis, and eczema. It has also been used as a tanning activator in sunscreens.
Too much copper can cause skin pigmentation because it boosts melanin production; this is a fairly rare occurrence because most people do not consume enough foods with copper in them for it to be a problem, however, it is possible. Foods that contain copper are leafy greens, like spinach, kale, and mustard greens, as well as whole grains, nuts, seeds, legumes, asparagus, and summer squash. Overdosing on beta carotene can cause temporary skin pigmentation, but the orange or red colour diminishes after a few hours.
Nutritional deficiencies can also cause skin discolouration, such as a lack of folic acid or PABA amino acids. Pregnant women and women who take birth control are especially susceptible to this type of skin pigmentation, however, it is usually temporary and can be cured by simply eating more foods with the required nutrients.