Dermatology is the field of medicine that deals with the diagnosis and treatment of diseases related to skin, hairs and nails. Before moving on to the common diseases of dermatology we need to understand the following terms.
1. Macule is a flat non palpable lesion with changes in skin color. Its size is less than 1 cm.
2. Patch is also a flat non palpable lesion with changes in skin color but the size is more than 1 cm.
3. Papule is a solid, elevated lesion and its size is less than 0.5 cm.
4. Nodule is a solid, elevated lesion and its size is more than 0.5 cm.
5. Plaque is an elevated, palpable, flat-topped lesion which is more than or equal to 1 cm in size.
6. Vesicle is a fluid (serous) filled raised Iesion of size less than or equal to 1 cm.
7. Bulla is a fluid (serous) filled raised lesion and its size is more than 1 cm.
8. Pustule is pus-filled raised lesion
9. Cyst is a nodule consisting of an epithelial-lined cavity filled with fluid or semi-solid material.
10. Scale is a think flake of dead exfoliated epidermis.
11. Crust is dried residue of skin exudates such as serum, pus, and blood.
12. Erosion is non-scarring loss of superficial epidermis.
13. Excoriation is a scratch mark (erosions caused by scratching)
14. Fissure is a liner crack in the skin, often resulting from excessive dryness.
15. Lichenification is chronic thickening of skin with increased skin markings.
16. Ulcer is a circumscribed loss of skin extending into the dermis.
17. Erythema is redness of skin due to vascular dilatation.
18. Petechia is a pinpoint macule of blood less than 1 to 2 mm. It does not blanch with pressure.
19. Purpura is a macule or papule of blood in skin. It is larger in size than a petechia and does not blanch with pressure.
20. Ecchymosis is larger confluent area of purpura and reassembles a bruise. 21. Telangiectasia is abnormally visible dilatation of blood vessels.
Some Common Allergic and Immune Mediated Disorders Are:
1. Urtricaria (Hives):
Utricaria is superficial, intense erythema and edema in a localized area of the body. It is a result of vasoactive mediators such as histamine released by the mast cells in type I hypersensitivity reaction. Type I hypersensitivity reaction is mediated by IgE antibodies.
It is classified on the basis of time for which the lesion last. If the lesion lasts for less than 24 hours it is called urtricaria. If the lesion lasts for more than 24 hours it is called urtricaria vasculitis. If the condition is present for less than 6 weeks it is said to be acute urtricaria and if the condition is present for more than 6 weeks it is said to be chronic urtricaria.
Triggers or antigens of utricaria include pollens, some foods, drugs like salicylates, antibiotics, codeine etc and venom of insects. Utricaria vasculitis can arise idiopathic, in SLE or hepatitis B.
Clinical Features: Urtricaria develops in areas that are prone to mechanical pressure such as trunks, extremities and ears. This is known as dermatographism. Angioedema is also seen, it refers to deeper and more diffuse swelling. It is mediated by IgE antibodies but if it is mediated by complement system then it is known as hereditary angioedema (it is due to deficiency of C1 inhibitors). Unlike eczema the edema is localized to perivascular spaces of superficial dermis.
It is treated by anti-histamines that are non-sedating in nature such as H1 blockers (loratidine). H2 blockers such as cimetidine are also considered in some patients. Stop any medication that is known to cause utricaria. Patients with feature of angioedema should carry a kit for self-administration of adrenaline.
2. Eczema:
Eczema is a Greek word which means “to boil over”. It consists of red, papulovesicular, oozing and crusted lesions that with persistence develop into raised and scaling plaques. Eczema and dermatitis are synonymous and these two words are used interchangeably. Spongiosis occur in eczema which is intracellular edema of epidermis. Unlike urtricaria it is not localized to a specific area. It seeps into the intracellular space of epidermis, splaying the keratinocytes apart.
Classification:
Eczema is either endogenous or exogenous. Endogenous include atopic eczema (dermatitis), discoid dermatitis, hand dermatitis, seborrheic dermatitis, venous dermatitis and asteatotic eczema. Exogenous include irritant contact eczema, allergic contact eczema, photosensitive eczema and lichen simplex.
A. Atopic Dermatitis:
It is a relapsing inflammatory skin disorder. It is genetically complex familial disease with a strong maternal influence. The exact pathophysiology of the disease is not fully understood but there is an initial activation of Th2-CD4 lymphocytes in the skin which is responsible for driving the inflammatory process.
Clinical features include itchy erythematous scaly patches that eventually leads to lichenification. It starts to appear in the face in children before spreading to the body. In adults it involves flexure surfaces such as in front of the elbows and ankles, behind the knee etc. Usually family history is positive for hay fever, asthma or eczema.
It is treated by avoiding the allergens or irritants, emollients are applied on the skin, wool cloths should be avoiding and cotton cloths should be used. Topical therapy of steroids and immunomodulators like Tacrolimus ointment is used. Adjunct therapy of oral antibiotics, sedating anti-histamines at night and paste bandaging is done.
B. Seborrheic Dermatitis:
It is a chronic inflammatory condition caused by the overgrowth of a fungus called Malassezia Furfur (Pityrosporum Ovale). A strong immune response is initiated against this yeast.
Clinical features of the disease are predilection of areas with oily skin, dandruff in adults and in infants “cradle cap” is formed. It is a thick crust on scalp. Leiner disease is a triad of generalized seborrheic dermatitis, failure to thrive and diarrhea. It is commonly seen in people with HIV and Parkinson disease. The common sites for inflammation are external auditory canal, scalp, forehead, retro auricular area and nasolabial fold.
Treated by combination of steroids ointment with topical antifungal cream, 2% Sulphur + 2% Salicylic acid are added to the therapy in resistant cases. Ketoconazole shampoo is an antifungal shampoo found useful in seborrheic dermatitis. Emollients and a soap substitute are useful adjuncts.
C. Contact Dermatitis:
Contact dermatitis is a type 4 hypersensitivity reaction that results from contact with an allergen to which the patient has been exposed and found allergic to. Contact dermatitis can be either be due to allergen or an irritant.
Allergic Contact Dermatitis occurs after repeated exposure to a chemical substance only in patients susceptible to develop allergic reaction. These allergens can be nickel, chromate, latex or perfumes.
Irritant Contact Dermatitis as the name suggest is due to exposure to an Irritant. Can occur in anyone. The common irritants responsible are detergents, soaps, bleaches, alkalis and acids.
3. Psoriasis:
It is a T cell mediated disease that involves increased keratosis proliferation with inflammation and formation of new vessels (angiogenesis). Clinical findings include salmon color plaques covered with silvery white scales that are present on extensor surfaces such as elbows and knees. Fingernail pitting is seen in 30% of the overall cases. It is strongly associated with streptococcal pharyngitis. Koebnerization is also evident. Auspitz sign can be appreciated which is pinpoint bleeding when scale is removed from plaque.
Psoriasis is associated with arthritis, spondylitic joint disease, myopathy, enteropathy and AIDS. Some common types of psoriasis are stable plaque psoriasis, flexure psoriasis, guttate psoriasis, erythrodermic psoriasis and pustular psoriasis. It is treated with tropical corticosteroids, calcitriol, tar and dithranol. Phototherapy can prove useful. Systemic agents such as Acitretin and methotrexate and cyclosporine can be used. Two regimes are used for psoriasis. One is Goeckerman regimen in which tar is given with UVB and the other one is Ingram regimen in which dithranol is given with UVB.
Conclusion:
Dermatology is an essential part of medicine dedicated to cure diseases related to human skin, hairs and nails. understanding all types of skin lesions such as macule, blisters, patch, papule and pustule etc are important for correct diagnosis of different diseases. Skin lesion can manifest in different ways often reflecting an underlying allergic or immune response.
Conditions like Eczema, psoriasis, urticaria and seborrheic dermatitis are pretty challenging but thanks to advancement in field of medicine researchers have discovered both topical and systemic therapies for them ensuring improved quality of life. By understanding dermatology and skin lesion we can better manage and prevent these conditions, leading to healthier skin and more confident life. If you liked this blog and want to know about bleeding and coagulation disorders click here. For more blogs related to human body go to my website Medrizz.com.
FAQs:
What is dermatology?
Dermatology is the branch of medicine that focuses on the diagnosis, treatment, and prevention of skin, hair, and nail disorders. It encompasses a wide range of conditions, from common skin issues like acne to more serious conditions such as psoriasis or skin cancer.
What are skin lesions?
Skin lesions are any abnormal changes in the skin’s appearance or structure. They can vary in shape, size, and color and can be caused by a variety of factors such as infections, allergies, injuries, or underlying medical conditions.
How is psoriasis treated?
Psoriasis is treated using a combination of topical treatments like corticosteroids, vitamin D analogs, and tar-based products. In severe cases, systemic treatments such as methotrexate, cyclosporine, or biologics may be used. Phototherapy, which involves ultraviolet (UV) light treatment, is also an option for some individuals.
Can skin lesions be a sign of something more serious?
Yes, while many skin lesions are benign and treatable, some may be indicative of more serious conditions, such as infections, autoimmune diseases, or even skin cancer. It is important to consult a dermatologist if you notice any unusual or persistent changes in your skin.
Can I prevent skin lesions?
While not all skin lesions can be prevented, maintaining healthy skin habits can reduce the risk. This includes using sunscreen regularly, avoiding harsh chemicals or irritants, managing stress, and keeping your skin moisturized. For certain conditions like eczema or psoriasis, identifying and avoiding triggers can help prevent flare-ups.