Dr Terrina Dickson looks at two possible causes of change in pigmentation.
Mrs M, a 34-year-old mother of two, presented complaining of brown patches on her face. These had been present since her early twenties and had worsened during pregnancy. She had been managing to cover the marks with make up, however, over the summer, she noticed that the areas were becoming more pigmented and more difficult to hide.
On examination Mrs M had symmetrical pigmented patches on her forehead and cheeks.
Chloasma or melasma occurs in genetically predisposed females and is more common in darker skin. It can occur in patients taking oral contraception and can develop during pregnancy - usually in the second to third trimester, however, it may also occur in females who are not pregnant or taking oral contraception.
Increased pigmentation develops slowly, most commonly affecting the forehead, cheeks, upper lip and chin. There is no sign of inflammation on examining the skin and pigmentation is generally, although not always, uniform.
The pigmentation may fade after pregnancy or when oral contraception is stopped. However, in some patients the pigmentation can be permanent.
Patients will generally notice that the pigmentation darkens with sun exposure and is less noticeable in the winter.
If Mrs M is on hormonal contraception she could consider stopping this. Bleaching creams containing hydroquinone are available OTC, and on prescription for higher concentrations.
These must be applied for at least six months to obtain a noticeable effect.
It is advisable to check for sensitivity before starting treatment.
Patients should be advised to use a broad-spectrum sunscreen to block UVA and UVB.
If the patient does not wish to undertake long-term treatment, referral to the Red Cross camouflage service can be useful. Patients are taught to apply camouflage make up and the products recommended can be provided on NHS prescription.
Kathy is a 13-year-old girl who reported white patches on her hands.
Her mother has vitiligo and she also has a younger sister who is affected.
Kathy was becoming embarrassed by her skin changes which were attracting comments from her peers.
She was otherwise well and had no signs of physical illness. Her skin showed no signs of inflammation but large depigmented areas were present on her hands, back and axillae. Routine bloods, including thyroid function tests, were normal.
Vitiligo affects approximately 1 per cent of the population and there is a positive family history in about a third of patients. The exact mode of inheritance is not clear. It is thought to be an autoimmune disorder and it is worth checking that the patient does not have any undiagnosed condition such as thyroid disease, pernicious anaemia or diabetes.
The commonest sites for vitiligo are the dorsa of the hands, intertriginous areas, face and genitalia. The depigmentation is more prominent against darker skin.
Strong topical corticosteroids can be useful in treating early patches of vitiligo. Some pigment may return but the side-effects often outweigh the potential benefits.
Again, referral to the Red Cross camouflage service can be useful. It is important that the patient uses a sunscreen with an SPF of 25 or higher, not only to minimise the damage to the depigmented skin, but also to reduce the pigmentation in the skin around the patches.
- Dr Dickson is a GP in Loanhead, Edinburgh and hospital practitioner at Royal Infirmary Edinburgh
- If you have a special interest in dermatology, you can register for free copies of MIMS Dermatology. Go to www.hayreg.co.uk/specials
LESSONS LEARNT FROM THESE EPISODES
- Chloasma or melasma occurs in genetically predisposed females and is more common in darker skin.
- It is linked to pregnancy and oral contraceptives.
- The pigmentation darkens with sun exposure and is less noticeable in the winter.
- Vitiligo is thought to be an autoimmune disorder.
- The Red Cross provides a camouflage service.
- Advise the use of broad-spectrum sun protection.