Acanthosis nigricans is often a forerunner of internal cancer. Therefore it is important to differentiate between the harmless benign acanthosis nigricans from the malignant variety of acanthosis nigricans, as early diagnosis of the causative tumor could be life saving.
How to Differentiate Benign from Malignant Acanthosis Nigricans?
If any of the following features are present in a patient with acanthosis nigricans, presence of internal cancer may be suspected and sought for:
- Age of onset: Benign acanthosis nigricans appear soon after birth, during childhood or in puberty. Late age of onset should arouse suspicion.
- Speed of Progression: If acanthosis nigricans appear and progress rapidly, it is indicative of a malignant origin, though not always. At times hormonal disorders may be the underlying cause.
- Severity of Skin Changes: In malignant acanthosis nigricans, the skin changes are more pronounced compared to the benign type of acanthosis nigricans. The dark color (pigmentation) is present beyond the area of thickening in malignant acanthosis nigricans.
- Distribution of Skin Lesions: In malignant acanthosis nigricans, there is extensive involvement of the skin, almost all folds and palms and soles and face are involved.
- Mucous membrane involvement: In contrast to the benign acanthosis nigricans, mucous membrane involvement is prominent in about 50% of malignant type of acanthosis nigricans.
- Skin Tags: Sudden appearance of skin tags in a case of acanthosis nigricans is indicative of serious underlying illness.
- Symptoms: Most benign acanthosis nigricans are asymptomatic. There is irritation and itching in the skin lesions of malignant acanthosis.
Tips on Dealing with Acanthosis Nigricans
There are certain do’s and don’ts in dealing with acanthosis nigricans. These are important in limiting the spread of the disease and finding the underlying causes.
Do’s in dealing with acanthosis nigricans:
The first course open to a patient is, of course, differentiating the benign from malignant variety of acanthosis nigricans, preferably with the help of a dermatologist. Certain skin diseases like confluent and reticulated papillomatosis, pigmented pityriasis versicolor, X-linked Icthyosis and retention hyperkeratosis have to be ruled out before diagnosing acanthosis nigricans.
- Diet control and regular exercise to reduce weight is essential in controlling acanthosis nigricans
- Diabetes, if present, should be brought under strict control through dietary restriction, exercises and effective medications
- In case of suspected malignant acanthosis nigricans, full panel of laboratory investigations should be carried out without much delay. Tumor markers, hormonal assays, endoscopy, Ultrasound and CT scans and whole body MRI are mandatory in such cases. The appearance of acanthosis nigricans can precede the full expression of cancer even by five years.
- Consultations with a general physician and a gastro-enterologist once in six months is advisable in progressive acanthosis nigricans where no primary focus could be found in previous checkups. The frequency should be increased in cases where the skin changes are rapidly progressing.
Any sudden progression of the skin condition along with appearance of skin tags or seborrheic keratosis (Leser Trelat Sign) calls for urgent medical consultation.
Don'ts in dealing with acanthosis nigricans:
There are certain things to be avoided in the presence of acanthosis nigricans:
- Most people think that the dirty appearance of the skin in acanthosis nigricans is due to dirt deposited on the skin. This results in constant and vigorous scrubbing of the involved skin. This should be avoided at any cost. Remember, skin is an organ where repeated rubbing and scrubbing increases the thickness and pigmentary deposit, rather than the opposite.
- Use of strong abrasives and soaps should also be avoided in acanthosis nigricans. These will only irritate the skin further.
How to Treat Acanthosis Nigricans
Treatment of acanthosis nigricans involves correction of the underlying cause and treatment of the skin lesions.
- Treatment of underlying cause. Finding and removing the underlying tumors, correction of hormonal imbalances, reduction of weight and stopping the offensive medication usually results in regression of the acanthosis nigricans in most patients, even without topical treatment.
- Some studies have shown the beneficial effects of fish oil supplements containing omega-3 fatty acids in reducing the severity of acanthosis nigricans.
- Cyproheptadine, an antiserotonin- antiallergic medication, has been found to be effective in causing regression of the skin lesions in some cases of acanthosis nigricans.
- Topical tretinoin and salicylic acid alone or in combination with steroids and alternating with moisturizers, form the backbone of the topical therapy of acanthosis nigricans.
- When the disease is not responding to the above measures, oral retinoids may be helpful in clearing the acanthosis nigricans.
Acanthosis nigricans as a marker of internal cancer is a serious condition which should be managed with the utmost caution. The management of acanthosis nigricans, as discussed above, involves early diagnosis and removal of the underlying causes.
Sources:
- Pavithran K et al. Disorders of Keratinization. IADVL Textbook of Dermatology. Eds, Valia RG & Valia AR. 3rd Ed. 995-1069; 2008.
- Fitzpatrick's Color Atlas & Synopsis of Clinical Dermatology, Fifth Ed, 2005
Disclaimer
The information given in this article is for educational purposes only so that patients are aware of the options available. No diagnosis should be made or treatment undertaken without first consulting your doctor. If you do so, the author or Suite101 will not be responsible for any consequences. The images provided are for illustration purpose only.
Hanish Babu - Dr.Hanish Babu, MD is a dermatologist and a feature writer on Suite101.com with more than 200 articles related to skin diseases on the ...
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