Sometimes it happens that you quickly develop red spots and/or welts when pressure or friction is applied to the skin. This phenomenon is called (positive) dermographism and is a harmless but above all a very annoying condition. Often no direct cause is found for this condition, but fortunately there are ways to alleviate the symptoms.
What is dermographism/urticaria factitia?
Dermographism or urticaria factitia is also popularly called medical drawing or medical tattooing. It is the phenomenon in which an itchy and red raised area occurs after rubbing or scratching. These resemble hives and can form large wheals that disappear after a few hours.
What actually happens in the skin?
The skin contains numerous mast cells. These cells contain a substance called histamine. Histamine is a chemical neurotransmitter that is produced, among other things, during an allergic reaction. Everyone knows symptoms of an allergic reaction such as swelling, itching and rash. With dermographism, histamine is released when the skin is rubbed.
How does dermografism arise?
In approximately 70-75% of cases, no cause is found for the condition. When it lasts longer than 6 weeks (acute phase) it transitions into the chronic phase and may take several years before it disappears. Some possible causes are:
- Medicines such as antibiotics, analgesics and contrast agents
- Allergy to foods such as strawberries, nuts, nuts and cow’s milk
- Contact allergies such as preservatives, latex, nickel and even soap products
- Insect bites including mosquitoes, ticks, fleas, lice, wasps, bees and horseflies
- Diseases: autoimmune diseases, hepatitis, metabolic diseases
- Physical stimuli: cold, heat, pressure, sunlight, effort
- Allergies to animals, more specifically dogs, cats and horses
It often happens that people used to not be allergic to a certain substance/product and suddenly they are. An allergy can also disappear/extinguish with age.
The occurrence of angioedema
Angioedema can occur together with dermographism and mainly occurs in the eyelids, cheeks, lips, genital area, back of the hand and the sole of the foot. This phenomenon also involves swelling. However, angioedema can also occur on mucous membranes such as the throat and tongue. In a severe acute reaction, one may experience respiratory distress and this is referred to as anaphylactic shock. It is vital to seek medical attention as soon as possible to prevent brain damage due to oxygen deficiency. Some people carry an Epipen (contains adrenaline) which can be administered by an outsider.
Although often no direct cause is found for the condition, treatment can be initiated. This treatment mainly relieves the symptoms (itching, rash, swelling).
What does the treatment consist of?
Nowadays there are medicines, or antihistamines, that can relieve the symptoms. Their purpose is to prevent the release of histamine. It is sometimes said that these medicines make people drowsy and sleepy. However, there are now more recent variants that have much less/no side effects.
Some examples of antihistamines are:
- Xyzall/Levocetirizine
- Zyrtec/Cetirizine
- Rupatall
- Atarax
It may help to rub the skin with a soothing lotion/cream. If the treatment is not very effective, corticosteroids can be used. Scratching should be avoided. Using cold packs and/or wet towels on the affected area can provide relief. Regular application prevents dry skin, which can also provoke a reaction.
What are the expectations?
In the acute phase, the urticaria may disappear after a few hours/days. Once the chronic phase has occurred, it can take months to years before the urticaria disappears. Symptoms can be alleviated by using antihistamines/corticosteroids.
