What is Skin Allergy?
An allergen is a substance that causes a hypersensitive adverse reaction in a person on contact with it. This contact can be through touch or inhalation. A skin allergy specifically pertains to an adverse (allergic) reaction when the skin, through touch, comes in contact with an allergen. The skin then develops uncomfortable symptoms like swelling, soreness, etc.
Symptoms of Skin Allergy
There are different types of skin allergies showing specific symptoms, but there are some symptoms commons to these allergies:
A) Redness of the affected skin
B) Constant and severe itching
C) Raised bumps (sometimes purulent or pus-filled)
D) Sensitivity of skin to extreme temperature changes
E) Extreme dryness of skin
F) Crusty skin lesions (in some cases)
G) Susceptibility of scratched skin to infections
Diagnosis of Skin Allergy
As skin allergy is a disease showing palpable signs, visual and physical examination itself will be sufficient to diagnose that the allergy is present. What remains to be identified is the type of allergen that has caused it in order to prescribe the accurate line of treatment. Also, the aim here is not just to alleviate the existing symptoms, but also the long-term prevention of recurrence.
History: In the case of allergies, whether of skin or otherwise, thoroughly going through the medical and family history is a very essential part of diagnosis. The doctor needs to check if there have been previous incidences of allergies in the patient (like allergic asthma) and whether the patient is consuming some medication for other ailments, etc to determine the possible cause of allergy. Also, some types of skin allergies may occur in more than one member of the family. Hence, checking the family history also is essential.
Blood tests: A blood test is undertaken in order to check for red blood and white blood cell count; blood type; presence of electrolytes; as well as levels of toxicity in the liver and kidney. Also, the types and levels of liver enzymes are examined to see if any of these could be the cause of allergic reaction. The blood test will also show a case of Angioedema, i.e. allergic reaction to medications.
Biopsy/scratch test: In severe cases, a biopsy and/or a scratch-swab-sample of the skin is sent for further analysis which would tell the type of skin allergy, the severity of the disease and the possible cause. This would enable the dermatologist to prescribe the correct course of treatment.
Causes of Skin Allergy
Skin allergens cause adverse reactions of the skin. Allergens could be in various forms like medications, chemical disinfectants, etc. But in some cases, there seems to be no apparent reason for the skin ailment.
Heredity: When the hypersensitive skin reaction is idiopathic (no apparent cause), then it is considered to have a hereditary or genetic cause. It is believed to be a reaction of the immune system to an internal unidentified allergen. In such cases, the family history would indicate that the ailment exists in more than one member of the family. The antibodies known as immunoglobulin E (IgE) or the basophils which release histamine into the system are considered the possible culprits.
Medications: Sometimes, long-term use of strong medications can cause skin allergies. This has been more noticeable in patients of heart failure and hypertension who are being treated with Angiotensin-Converting Enzyme inhibitors (ACE inhibitors).
Viruses: Exanthem or acute urticaria is a skin allergy caused by viral infection.
Bacteria: Helicobacter pylori or Streptococcus bacteria also cause some types of skin allergies.
Chemicals/soaps: Some people need to handle chemicals like disinfectants, strong detergents, mineral oils, chlorine, formaldehyde, etc on a regular basis. If the chemicals are accidentally handled without protective clothing or if strong fumes of the chemical are inhaled, this can be a cause for a skin allergy. People are sometimes allergic to particular types of soaps. The allergen would cause extreme dryness of skin, irritation and itchiness. Scratching would further aggravate the situation.
Metals: Some people are allergic to contact with metals like nickel or even silver and gold. They develop skin allergies whenever they wear ornaments made from these metals.
Strong smells: Some people are allergic to perfumes, fragrances like aromatic flowers, etc. They would not only experience severe sneezing or coughing reactions, but in some cases also a skin allergy.
Fabric: Use of certain synthetic fabrics such as nylon, polyesters, etc or even synthetic woolen garments can cause allergic skin reactions in some people.
Food: Certain foodstuff like caffeine, nuts, wheat, sour tomatoes or tamarind, milk and milk products, egg, soy beans, shellfish, etc can cause allergic skin reactions along with other internal allergic reactions.
Sunlight: Too much exposure to ultraviolet rays of the sun can also cause an allergic skin reaction in some people.
Types of Skin Allergy
Hives: Also, called urticaria, this is an idiopathic (no known cause) type of skin allergy. It is believed to be a hypersensitive skin reaction of the epidermis to an unidentified internal trigger, usually genetic in nature. This can also be caused by food allergies. The symptoms usually last for about 5 weeks in the case of acute form and 3 months or longer in the case of chronic urticaria. The symptoms would appear as extremely itchy and deep red bumps or boils on the skin. Urticaria caused by viruses and bacteria can occur but is less common.
Angioedema: Also called Quincke’s edema, this is a hypersensitive skin reaction of the dermis and subcutaneous tissue to medications for respiratory disorders, diabetes, cardiovascular disorders, etc. Research shows that the usual culprits are Angiotensin Converting Enzyme (ACE) inhibitors (for heart ailments), sulphonylurea glimepiride (for diabetics), aspirin, anticonvulsants, dextroamphetamine, sulfonamides, penicillin, etc.
Caution: When Angioedema and urticaria occur simultaneously in the throat, this is an emergency situation due to suffocation and obstruction of the air passages.
Atopic Dermatitis: Also called Eczema, in this type of skin allergy the symptoms like itchiness, thickening of skin, dryness of skin, redness, etc keep subsiding and recurring over a long period of time. These episodes are called flares (appearing) and remissions (subsiding). Diagnostic tests of patients show a high level of the immunoglobulin E (IgE) indicating a genetic cause. Also, the skin is susceptible to viral and bacterial infection due to recurrence of symptoms and scratching. This affects the palms, hands, feet and nipples most severely.
Treatment of Skin Allergy
The treatment of skin allergies would focus more on eliminating the trigger or allergen causing the disease. As the allergen would differ from patient to patient, there is no standardized procedure of treatment. Also, the temperature of bath water should be moderate or lukewarm so as not to aggravate the symptoms. But there are a few methods of treatment followed:
Antihistamines: Histamine antagonists like H1 receptor, hydroxyzine, diphenhydramine or cetirizine are commonly used to reduce the symptoms as also to lengthen the remission period. H2 receptor (ranitidine or cimetidine) is used infrequently and only in very severe cases.
Antidepressants: Medications like doxepin may also be prescribed in some cases, although the side effects act as deterrents.
Steroids: Corticosteroid injections of prednisone, cortisone, and triamcinolone are prescribed when the ailment is very severe.
B) Topicals: Steroidal creams or ointments like hydrocortisone 1% are prescribed for reducing inflammation and itching of the skin. Immuno-suppressants like pimecrolimus or tacrolimus are also used. Moisturizers and lotions containing lanolin and mineral oil are suggested to reduce dryness of the skin and to re-hydrate the skin. Special humectants like propylene glycol or sorbitol are prescribed, which add moisture from the air onto the skin. These break down the dry crusts formed on the skin.
C) Indian herbal oils: Neem oil and sandalwood oil massages help not only to cure the rash and itchiness, but also act as natural moisturizers and re-hydrators.
D) Phototherapy: In this method of treatment, the affected skin is exposed to ultraviolet A and B waves under controlled conditions. Also, in some cases, photochemotherapy is undertaken, which is a combination of phototherapy and the use of the drug psoralen.
E) Diet: Food intolerance has to be identified in case of skin allergies caused by foodstuff. Complete elimination of these products from the patient’s diet becomes a necessary part of the treatment.
F) Skin care: Skin care as a part of the treatment involves avoiding the causative allergen; bathing with lukewarm water as extreme temperatures will aggravate the symptoms; using soft bath gels with no additives like fragrances; using moisturizers to re-hydrate the skin; using garments made from soft cotton (no synthetic fabrics), etc. Also, experimentation with untried cosmetics should be avoided.
G) Psychological pain management: This would involve relaxation techniques like yoga and meditation, stress management advice and “talk-for-relief” group therapies.
H) Acupunture: This method involves piercing the skin with extremely thin needles at specific pressure points on the body which stimulate specific organs. The needle-puncture would stimulate the flow of blood as well as the level of natural antihistamines like neurohormones and neurotransmitters.
Living with Skin Allergy
Skin allergies, although not life-threatening, do take control of the day-to-day life of a patient. A lot of adjustment and life-style changes need to be implemented. The diet should be free of all types of possible allergy-causing foodstuff (listed above). The patient needs to avoid extreme weather conditions. Medications may sometimes cause side effects, which again would have a debilitating effect. In the case of recurrent symptoms, the cost of treatment becomes prohibitive.
Prevention of Skin Allergy
As dryness of the skin is one of the major symptoms of skin allergies, keeping the skin moist and hydrated would be the key to prevention. Some measures are:
1) Avoid contact with the usual allergens listed above (including foodstuff)
2) Use moisturizers to hydrate skin as a routine
3) Avoid garments made from synthetic fabrics
4) Use humidifiers in the house if the climate is too dry
5) Use rubber gloves while handling detergents, disinfectants, etc
6) Use gentle soaps which are not alkaline
7) Avoid scratching any insect bites which could get infected
8) Avoid strong perfumes and fragrances
9) Avoid emotional stress, which might over-activate the immune system, etc.