Medical Dermatology

Urticaria, commonly known as hives, is a skin reaction characterized by raised, red, itchy welts (also called wheals) that can appear anywhere on the body. These welts may vary in size and shape, and they often appear suddenly and resolve within hours, though in some cases, they can persist for weeks or longer. Urticaria can be acute (short-term) or chronic (long-lasting).

Types of Urticaria:

1. Acute Urticaria:
   • Lasts less than 6 weeks.
   • Often triggered by an allergen, infection, or other temporary factor.
2. Chronic Urticaria:
   • Persists for more than 6 weeks, with recurring episodes.
   • May not have an identifiable cause and is often considered idiopathic.
3. Physical Urticaria:
   • Triggered by physical stimuli, such as pressure, cold, heat, sunlight, or vibration.
4. Angioedema:
   • Swelling of the deeper layers of the skin, often associated with urticaria. It can affect the lips, eyelids, and throat, and in severe cases, it may impair breathing.

Causes and Triggers:

• Allergic Reactions:
  • Foods (e.g., nuts, shellfish, eggs)
  • Medications (e.g., penicillin, aspirin, NSAIDs)
  • Insect stings or bites
• Non-Allergic Triggers:
  • Infections (viral, bacterial, or parasitic)
  • Physical factors (cold, heat, sunlight, water, pressure)
  • Stress or emotional factors
  • Hormonal changes
  • Exercise-induced urticaria
• Idiopathic: In many chronic cases, no specific cause is identified.

Symptoms:

• Welts (Wheals):
  • Raised, red or skin-colored, and often surrounded by a pale halo.
  • Can vary in size from small dots to large patches.
• Itching:
  • Intense itching is a hallmark symptom, although some may experience burning or stinging.
• Transient Nature:
  • Individual hives usually resolve within 24 hours, though new ones may appear elsewhere.
• Angioedema (in some cases):
  • Swelling of deeper tissues, particularly around the eyes, lips, hands, feet, or throat.
• Systemic Symptoms (Rare):
  • Severe allergic reactions (anaphylaxis) may include difficulty breathing, wheezing, dizziness, or swelling in the throat. This is a medical emergency.

Diagnosis:

1. Clinical History:
   • Detailed history of symptoms, potential triggers, and any associated factors like medications or recent infections.
2. Physical Examination:
   • Evaluation of the pattern, location, and duration of hives.
3. Allergy Testing:
   • Skin prick tests or blood tests (e.g., IgE levels) to identify potential allergens.
4. Blood Tests:
   • To rule out underlying conditions like autoimmune diseases or infections.
5. Challenge Tests:
   • For physical urticaria, exposure to the suspected trigger under controlled conditions (e.g., cold, heat, or pressure).

Treatment:

1. Antihistamines:
   • First-line treatment: Non-sedating antihistamines (e.g., loratadine, cetirizine) are used to block the histamine response.
   • In severe cases, sedating antihistamines (e.g., diphenhydramine) may be used.
2. Corticosteroids:
   • For severe or persistent cases, a short course of oral corticosteroids (e.g., prednisone) may be prescribed.
3. Avoiding Triggers:
   • Identifying and avoiding known triggers can prevent future episodes.
4. Epinephrine (Adrenaline):
   • Used in emergencies, such as anaphylaxis, to counteract severe allergic reactions.
5. Chronic Urticaria Management:
   • Omalizumab (Xolair): An injectable medication for chronic idiopathic urticaria that does not respond to antihistamines.
   • Cyclosporine: An immunosuppressant used in refractory cases.
6. Lifestyle Adjustments:
   • Wearing loose, comfortable clothing.
   • Using cooling agents or soothing creams to relieve itching.

Prognosis:

• Acute Urticaria: Usually resolves within hours to weeks and does not recur once the trigger is removed.
• Chronic Urticaria: Can persist for months or years but often resolves over time.
• With appropriate treatment and trigger management, most cases can be effectively controlled.

Pityriasis rosea is a self-limiting, inflammatory skin condition that typically causes a distinctive rash. It is most common in adolescents and young adults, though it can affect people of all ages. The condition is generally mild and resolves on its own within 6 to 8 weeks, though it can cause temporary discomfort or cosmetic concern due to the appearance of the rash.

Key Features:

• Herald Patch: The condition often begins with a single, large, oval-shaped, pink or red patch (herald patch) that appears on the chest, back, or abdomen. It is often scaly and may be slightly raised.
• Secondary Rash: Within 1 to 2 weeks, smaller, more numerous, oval patches appear, often arranged in a pattern that follows the lines of the ribs on the back (resembling a “Christmas tree” pattern). These patches are usually pink or salmon-colored with a fine scale on the surface.
• Itching: The rash may cause mild to moderate itching, though it is typically not painful.

Causes:

• Viral Infection: While the exact cause of pityriasis rosea is unknown, it is believed to be linked to viral infections, particularly the human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7). However, the condition is not contagious.
• Possible Triggers: In some cases, the condition may be triggered by other factors, such as stress, seasonal changes, or certain medications, although these triggers are not fully understood.

Risk Factors:

• Age: Pityriasis rosea most commonly affects individuals between the ages of 10 and 35.
• Seasonal Variation: The condition is more common in the spring and fall, which may suggest a link to environmental factors or viral activity.
• Previous Viral Infections: Individuals who have had viral infections, particularly HHV-6 or HHV-7, may be at higher risk.

Symptoms:

• Herald Patch: The initial large patch is often the first noticeable symptom, appearing as a pink or red, oval-shaped lesion, usually on the trunk or upper arms.
• Secondary Rash: The rash spreads in a pattern across the body, often along the ribs and on the back, with smaller oval patches that may have a fine, scaly texture.
• Itching: Some people experience itching, which can range from mild to moderate.
• Mild Fever or Malaise: In some cases, patients may have mild flu-like symptoms, such as a low-grade fever or feeling unwell, although these symptoms are not common.
• Skin Lesions: The patches are typically flat or slightly raised, with a fine, scaly surface. The skin can also appear slightly pink to red, with a uniform appearance.

Diagnosis:

• Clinical Examination: Diagnosis is primarily based on the appearance of the rash and medical history. The characteristic “Christmas tree” pattern on the back is a key indicator.
• Skin Biopsy: In uncertain cases, a skin biopsy can be performed to confirm the diagnosis and rule out other skin conditions.
• Laboratory Tests: Blood tests or swabs may be done to rule out other infections if needed, although these are rarely necessary for a clear diagnosis.

Treatment:

• Supportive Care: Since pityriasis rosea is self-limiting, it usually resolves on its own without medical treatment. Symptom management is typically focused on controlling itching and discomfort.
  • Topical Steroids: Mild corticosteroid creams can help reduce inflammation and itching.
  • Antihistamines: Oral antihistamines (such as diphenhydramine or loratadine) can help manage itching.
  • Moisturizers: Applying moisturizing lotions or creams can soothe dry, itchy skin.
  • Oatmeal Baths: Soaking in colloidal oatmeal baths may also help relieve itching.
• Sun Exposure: Moderate sun exposure can sometimes help speed up healing, but sunburn should be avoided, as it can worsen symptoms.
• Oral Antihistamines or Steroids: In severe cases or if the itching is particularly bothersome, oral antihistamines or low-dose oral steroids may be prescribed.

Prognosis:

• Self-Limiting: Pityriasis rosea typically resolves on its own within 6 to 8 weeks, and the skin usually returns to normal without scarring.
• Recurrence: Rarely, pityriasis rosea may recur, but this is uncommon.
• Scarring: Scarring is also uncommon, although hyperpigmentation or hypopigmentation (dark or light spots) may remain temporarily after the rash resolves, especially in individuals with darker skin tones.

Onychomycosis is a fungal infection of the nails, most commonly affecting the toenails, though it can also affect fingernails. It is caused by dermatophytes, yeasts, or molds that invade the nail and surrounding tissues, leading to changes in the appearance and texture of the nail. Onychomycosis is often persistent and may require prolonged treatment.

Causes:

• Dermatophytes: These are the most common cause of onychomycosis and are fungi that thrive in warm, moist environments. Common dermatophytes include Trichophyton rubrum and Trichophyton mentagrophytes.
• Yeasts: Candida albicans, a type of yeast, can also cause onychomycosis, especially in fingernails or in individuals with compromised immune systems.
• Molds: Some molds, like Aspergillus and Fusarium, can cause onychomycosis, but they are less common.

Risk Factors:

• Age: Onychomycosis becomes more common with age, as nails grow more slowly and may become brittle.
• Poor Foot Hygiene: Wearing damp shoes, socks, or walking barefoot in communal places like pools can increase risk.
• Underlying Health Conditions: Diabetes, peripheral vascular disease, and immune system disorders (e.g., HIV/AIDS) can increase susceptibility to fungal infections.
• Trauma to the Nail: Injury to the nail or nail bed can create an entry point for fungal infection.
• Warm, Humid Environments: Fungi thrive in moist environments, making individuals who wear tight or non-breathable footwear or live in humid climates more prone to infection.

Symptoms:

• Discoloration: The nail may become yellow, brown, or white, with possible dark streaks or spots.
• Thickening of the Nail: The infected nail may become thick and difficult to trim.
• Crumbly or Brittle Nails: The nail may become fragile, cracking or crumbling at the edges.
• Distortion of the Nail Shape: The nail may become misshapen, pitted, or detaching from the nail bed (onycholysis).
• Odor: A fungal infection can sometimes produce a foul odor from the affected nail.
• Pain or Tenderness: In more severe cases, the nail may become painful, especially if the infection extends to the surrounding tissue.

Diagnosis:

• Clinical Examination: A doctor or dermatologist may diagnose onychomycosis based on the appearance of the nails and medical history.
• Laboratory Tests:
  • Microscopic Examination: A sample from the nail (scraping) can be examined under a microscope to identify fungal cells.
  • Fungal Culture: A culture may be done to identify the specific fungus causing the infection.
  • PCR Testing: Polymerase chain reaction (PCR) testing can detect fungal DNA in the nail sample.

Treatment:

1. Topical Antifungal Medications:
   • Efinaconazole (Jublia) and Ciclopirox (Penlac) are commonly prescribed topical treatments that can help treat mild to moderate onychomycosis.
   • These treatments may be less effective than oral medications but are suitable for less severe cases or patients with contraindications to oral therapy.
2. Oral Antifungal Medications:
   • Terbinafine (Lamisil) and Itraconazole (Sporanox) are the most commonly prescribed oral antifungals for onychomycosis. They work by targeting the fungal infection from the inside, offering a more effective treatment for severe or widespread infections.
   • These treatments typically require several weeks or months of therapy.
3. Nail Debridement:
   • In some cases, removing or trimming the infected nail can help improve the effectiveness of topical treatments or allow for better healing.
4. Laser Treatment:
   • Laser therapy can be used to target and kill the fungi in the nail. It is considered an adjunctive treatment and is often used for patients who cannot take oral medications.

Prevention:

• Good Foot Hygiene: Wash feet daily, dry thoroughly, especially between toes, and change socks regularly.
• Avoid Sharing Personal Items: Do not share towels, nail clippers, or shoes, as fungi can spread through contact.
• Wear Breathable Shoes and Socks: Choose footwear that allows the feet to breathe and avoid wearing damp socks or shoes.
• Protect Nails in Public Spaces: Wear flip-flops or waterproof shoes in communal areas like swimming pools, locker rooms, and showers.
• Trim Nails Properly: Keep nails trimmed and filed to prevent trauma that can lead to infection.

Telogen effluvium is a common form of hair loss that occurs when a significant number of hair follicles prematurely enter the telogen (resting) phase of the hair growth cycle. This leads to excessive shedding of hair and noticeable thinning, typically a few months after a triggering event or stressor.

Hair Growth Cycle:

• Anagen Phase (Growth Phase): The active phase when hair is growing.
• Catagen Phase (Transitional Phase): A short phase where hair stops growing and detaches from its follicle.
• Telogen Phase (Resting Phase): Hair remains in the follicle but does not grow. After this phase, hair sheds and is replaced by new hair.

In telogen effluvium, a large number of hairs prematurely enter the telogen phase, resulting in hair shedding. Typically, 85-90% of hair is in the anagen phase, and 10-15% is in the telogen phase at any given time. In telogen effluvium, the percentage of hairs in the telogen phase can rise significantly, leading to noticeable shedding.

Causes and Triggers:

Telogen effluvium is often triggered by stressors or changes in the body that disrupt the normal hair growth cycle. Common causes include:

1. Physical or Emotional Stress:
   • Severe illness (e.g., fever, infection, surgery)
   • Emotional stress or trauma (e.g., death, divorce, major life changes)
   • Childbirth (postpartum telogen effluvium is common)
2. Nutritional Deficiencies:
   • Iron deficiency, protein deficiency, or other nutrient imbalances.
3. Hormonal Changes:
   • Pregnancy, menopause, or thyroid disorders can trigger telogen effluvium.
4. Medications:
   • Certain drugs, such as chemotherapy, anticoagulants, or antidepressants, can lead to hair shedding.
5. Infections:
   • Fungal or bacterial infections can sometimes cause telogen effluvium.
6. Environmental Factors:
   • Significant environmental changes like extreme heat or cold exposure, toxins, or pollution.

Symptoms:

• Hair Thinning: Noticeable thinning of hair, especially on the scalp.
• Excessive Shedding: An increase in hair loss during washing or brushing.
• Diffuse Pattern: Hair loss is often widespread and not localized to one area.

Diagnosis:

• Clinical Evaluation: Based on history and pattern of hair loss, and identification of recent stressors or changes in health.
• Pull Test: A test where a small amount of hair is gently pulled to check for increased shedding.
• Scalp Biopsy: In rare cases, a biopsy may be done to rule out other causes of hair loss.
• Blood Tests: To check for underlying causes like thyroid disorders or nutritional deficiencies.

Treatment:

1. Addressing the Underlying Cause:
   • If the trigger (e.g., stress, illness, or nutritional deficiency) can be identified and treated, the hair may begin to regrow on its own.
2. Hair Growth Products:
   • Minoxidil (Rogaine) may help stimulate hair regrowth, although results can vary.
3. Nutritional Supplements:
   • Iron, vitamin D, biotin, and other supplements may be recommended if deficiencies are identified.
4. Stress Management:
   • Stress reduction techniques such as meditation, exercise, or therapy may help in cases triggered by emotional stress.

Prognosis:

• Temporary: Telogen effluvium is usually temporary, and hair often begins to regrow within 6-12 months after the trigger is addressed.
• Recovery: In most cases, once the underlying cause is resolved, the hair returns to its normal growth cycle.
• Chronic Cases: In some individuals, telogen effluvium may persist for months or become a recurrent issue, especially if the underlying trigger is not managed.

Androgenic alopecia is a hereditary form of hair loss commonly referred to as male-pattern baldness in men and female-pattern hair loss in women. It is caused by a combination of genetic factors and hormonal influences, specifically the effect of androgens (male hormones such as testosterone) on hair follicles.

Key Features:

• Male-Pattern Baldness:
  • Begins with a receding hairline and thinning at the crown of the head.
  • Over time, the hairline recedes further, and the hair at the top of the scalp becomes thinner and may eventually bald.
• Female-Pattern Hair Loss:
  • In women, the hair loss tends to be more diffuse across the scalp, with thinning mainly at the crown and part line. The hairline typically remains intact.

Causes:

1. Genetics:
   • A family history of androgenic alopecia is the most significant risk factor. The genetic predisposition affects how hair follicles respond to androgens.
2. Hormonal Factors:
   • Dihydrotestosterone (DHT), a derivative of testosterone, shrinks hair follicles over time, leading to shorter and finer hair. In men, DHT is the main culprit behind male pattern baldness. In women, hormonal changes such as those during menopause can contribute to hair thinning.
3. Age:
   • Androgenic alopecia typically starts in adulthood and progresses with age.

Symptoms:

• Gradual Thinning: Thinning of hair, particularly at the temples, crown, or part line.
• Receding Hairline: In men, hair loss often begins at the temples, leading to a characteristic “M” shape of the hairline.
• Balding Areas: In both men and women, the affected areas become more noticeable, and scalp becomes more visible as the hair becomes finer.
• Minimal Scalp Inflammation: Unlike other types of hair loss, androgenic alopecia typically does not cause significant scalp redness or irritation.

Diagnosis:

• Clinical Examination: A healthcare provider will examine the pattern of hair loss and ask about family history.
• Scalp Biopsy: In some cases, a biopsy of the scalp can be done to confirm the diagnosis and rule out other causes of hair loss.
• Blood Tests: To rule out other underlying conditions like thyroid problems or iron deficiency.

Treatment Options:

1. Medications:
   • Minoxidil (Rogaine): A topical treatment that stimulates hair growth and prevents further hair loss.
   • Finasteride (Propecia): An oral medication that blocks the conversion of testosterone to DHT, slowing hair loss in men.
   • Spironolactone: A medication for women that can block androgen receptors and reduce the effects of DHT on hair follicles.
2. Hair Transplant Surgery:
   • Involves removing hair follicles from areas of the scalp where hair is still growing and transplanting them into balding areas.
3. Platelet-Rich Plasma (PRP) Therapy:
   • Involves injecting concentrated platelets from the patient’s blood into the scalp to promote hair regrowth.
4. Laser Therapy:
   • Low-level laser therapy (LLLT) can help stimulate hair follicles and promote hair regrowth.

Prevention and Lifestyle:

• Sun Protection: Protecting the scalp from excessive sun exposure may help prevent further hair loss.
• Stress Management: While androgenic alopecia is mainly genetic, chronic stress can exacerbate hair thinning.
• Healthy Diet: Ensuring adequate nutrition can help maintain hair health, although it won’t reverse hair loss.

Prognosis:

• Androgenic alopecia is a progressive condition, and while treatments can help slow down or manage hair loss, they may not fully restore hair to its original density. The extent of hair loss varies from person to person. Early treatment can provide better outcomes, especially in preventing further thinning or balding.

Spider angiomas are common, benign vascular lesions that appear as small, red spots with radiating blood vessels resembling a spider’s web. They are caused by dilated capillaries near the surface of the skin. Spider angiomas are also known as spider telangiectasias or nevus araneus.

Appearance:

• Central Red Dot: A bright red spot in the center.
• Radiating Vessels: Thin, reddish lines spreading outward, resembling a spider’s legs.
• Blanching: Pressing on the lesion causes it to temporarily disappear, with the color returning once pressure is released.

Common Locations:

• Face
• Neck
• Chest
• Arms
• Hands

Causes and Risk Factors:

Spider angiomas may occur in both healthy individuals and as a sign of underlying conditions. Common causes include:

1. Physiological Causes:
   • Seen in children and pregnant women due to hormonal changes.
2. Liver Disease:
   • Associated with cirrhosis or chronic liver disease due to elevated estrogen levels.
3. Hormonal Influence:
   • High levels of estrogen, such as during pregnancy or with oral contraceptive use.
4. Other Conditions:
   • Thyroid disorders or certain autoimmune diseases.
5. Idiopathic:
   • Occurs without an identifiable cause.

Diagnosis:

• Clinical Examination:
  • Diagnosis is typically based on the characteristic appearance of the lesion.
• Further Testing:
  • If spider angiomas are widespread or accompanied by other symptoms, liver function tests or hormonal assessments may be performed.

Treatment:

Spider angiomas are often harmless and do not require treatment unless for cosmetic reasons or if they indicate an underlying condition. Treatment options include:

1. Laser Therapy:
   • Pulsed-dye lasers can effectively remove the lesions.
2. Electrocautery:
   • Using heat to destroy the dilated vessels.
3. Underlying Condition Management:
   • Treating liver disease or discontinuing hormonal medications can reduce the appearance of new lesions.

Prognosis:

• Spider angiomas are benign and not cancerous.
• They may resolve spontaneously, especially in children or after pregnancy.
• Persistent or increasing numbers of spider angiomas, particularly with other symptoms, warrant medical evaluation to rule out underlying conditions like liver disease.

Post-inflammatory hyperpigmentation (PIH) is a common condition in which dark spots or patches of discoloration develop on the skin after it experiences injury or inflammation. It results from an overproduction of melanin (the skin pigment) in response to the inflammatory process. PIH can occur in all skin types but is more common and pronounced in individuals with darker skin tones.

Causes of PIH:

PIH occurs when the skin produces excess melanin during the healing process of inflammation or injury. Common triggers include:

• Acne: A frequent cause, leaving dark spots after pimples heal.
• Eczema and Dermatitis: Chronic inflammation can result in discoloration.
• Injuries: Cuts, burns, or abrasions.
• Infections: Fungal or bacterial infections of the skin.
• Cosmetic Procedures: Laser treatments, chemical peels, or dermabrasion.
• Irritation: Caused by harsh skincare products or over-exfoliation.

Symptoms:

• Appearance: Flat areas of discoloration ranging from light brown to black, depending on skin tone and severity.
• Location: Found at the site of previous inflammation or injury.
• No Physical Symptoms: Typically does not cause itching, pain, or discomfort.

Risk Factors:

• Darker Skin Tones: Higher melanin content increases the likelihood and visibility of PIH.
• Sun Exposure: Exacerbates hyperpigmentation by stimulating melanin production.
• Chronic Inflammation: Prolonged or repeated inflammatory episodes increase risk.

Diagnosis:

PIH is usually diagnosed through:

• Clinical Examination: Based on medical history and the appearance of the skin.
• Wood’s Lamp Examination: A special light may be used to determine the depth of pigmentation (epidermal or dermal).

Treatment:

1. Topical Therapies:
   • Skin-Lightening Agents: Hydroquinone, azelaic acid, kojic acid, or niacinamide.
   • Retinoids: Such as tretinoin or adapalene, to promote skin cell turnover.
   • Vitamin C: Reduces melanin production and brightens skin.
2. Sun Protection:
   • Daily use of broad-spectrum sunscreen (SPF 30 or higher).
   • Avoid excessive sun exposure, as UV light worsens pigmentation.
3. Professional Procedures:
   • Chemical Peels: Use of glycolic acid, salicylic acid, or other agents to exfoliate pigmented skin.
   • Laser Therapy: Specific lasers target pigmented areas but require caution in darker skin tones.
   • Microneedling: Stimulates skin renewal and can help improve discoloration.
4. Over-the-Counter Products:
   • Formulations containing alpha hydroxy acids (AHAs) or beta hydroxy acids (BHAs).

Prevention:

• Avoid picking or scratching at acne or skin injuries.
• Use gentle skincare products to minimize irritation.
• Treat inflammatory skin conditions promptly to reduce the risk of PIH.

Prognosis:

PIH often fades over time but may take months or years, depending on the depth of pigmentation and individual factors. Early treatment and diligent sun protection can significantly speed up improvement and prevent worsening.

Candidiasis is a fungal infection caused by yeasts belonging to the genus Candida, most commonly Candida albicans. It can affect the skin, nails, or mucous membranes and ranges from mild to severe infections depending on the site and underlying health conditions.

Types of Candidiasis:

1. Cutaneous Candidiasis: Affects the skin, often in warm, moist areas such as skin folds (e.g., armpits, groin, under the breasts).
2. Onychomycosis (Nail Candidiasis): Involves infection of the nails, leading to discoloration, thickening, and brittleness.
3. Mucosal Candidiasis:
   • Oral Thrush: Affects the mouth and throat, appearing as white patches.
   • Vaginal Candidiasis (Yeast Infection): Common in women, causing itching, discharge, and discomfort.
   • Esophageal Candidiasis: Affects the esophagus, usually in immunocompromised individuals.

Symptoms:

1. Cutaneous Candidiasis:
   • Red, itchy rash with satellite lesions (smaller red spots around the main rash).
   • Cracked, sore skin in affected areas.
2. Nail Candidiasis:
   • Yellow or white discoloration of nails.
   • Thickened or brittle nails, sometimes with pain or swelling.
3. Oral Thrush:
   • White patches on the tongue, inner cheeks, or throat.
   • Painful, burning sensation, and difficulty swallowing.
4. Vaginal Candidiasis:
   • Itching, redness, and swelling of the vulva.
   • Thick, white discharge with a cottage cheese-like texture.
   • Burning sensation during urination or intercourse.
5. Esophageal Candidiasis:
   • Painful swallowing and chest pain.

Risk Factors:

• Weakened Immune System: E.g., HIV/AIDS, chemotherapy, or organ transplantation.
• Antibiotic Use: Disrupts the balance of normal flora, allowing Candida overgrowth.
• Diabetes Mellitus: High blood sugar levels promote fungal growth.
• Hormonal Changes: Pregnancy, birth control pills, or hormone replacement therapy.
• Moisture and Warmth: Prolonged damp conditions, such as sweating or wet clothing.

Herpes Simplex Virus (HSV) infections are caused by a group of viruses known as herpes simplex viruses, primarily HSV-1 and HSV-2. These viruses cause recurrent, lifelong infections and manifest as painful blisters or sores on the skin and mucous membranes.

Types of HSV Infections:

1. HSV-1 (Oral Herpes):
   • Primarily causes cold sores or fever blisters around the mouth or face.
   • Can also infect the genital area through oral-genital contact.
2. HSV-2 (Genital Herpes):
   • Commonly associated with genital and anal infections.
   • Spread through sexual contact.

Symptoms of HSV Infections:

• Primary Infection:
  • Painful blisters or ulcers at the site of infection.
  • Flu-like symptoms such as fever, headache, and swollen lymph nodes.
• Recurrent Episodes:
  • Less severe than the primary infection.
  • Tingling, itching, or burning may precede sores (prodromal symptoms).
• Latency and Reactivation:
  • After the initial infection, the virus remains dormant in nerve cells.
  • Reactivation can be triggered by factors such as stress, illness, fatigue, or sun exposure.

Transmission:

• Direct Contact: Through skin-to-skin contact with infected lesions or mucosal surfaces.
• Asymptomatic Shedding: The virus can spread even in the absence of visible sores.
• Neonatal Transmission: From an infected mother to the baby during childbirth (neonatal herpes).

Diagnosis:

1. Clinical Examination: Based on the appearance of sores or blisters.
2. Laboratory Tests:
   • Viral culture or PCR (polymerase chain reaction) to detect viral DNA.
   • Serological tests to detect HSV-specific antibodies.

Contact dermatitis is a skin condition characterized by inflammation resulting from direct contact with an irritant or allergen. It presents as a red, itchy rash that may involve swelling, blistering, or dry, cracked skin, depending on the severity and type of exposure.

Types of Contact Dermatitis:

1. Irritant Contact Dermatitis:
   • Caused by direct damage to the skin’s protective barrier from irritants like chemicals, detergents, or solvents.
   • Common and non-allergic in nature.
2. Allergic Contact Dermatitis:
   • A delayed hypersensitivity reaction to an allergen that activates the immune system.
   • Examples include nickel, latex, poison ivy, fragrances, or certain cosmetics.

Symptoms:

• Erythema (Redness): Commonly seen at the site of contact.
• Pruritus (Itching): Often intense.
• Vesicles or Bullae: Blisters filled with clear fluid (more common in allergic reactions).
• Scaling and Crusting: With chronic or repeated exposure.
• Swelling: Sometimes localized to the affected area.
• Burning or Stinging: Particularly in irritant contact dermatitis.

Diagnosis:

• Clinical History: Identifying possible exposures.
• Patch Testing: Used to identify allergens in suspected allergic contact dermatitis.
• Skin Examination: To rule out other conditions like atopic dermatitis or psoriasis.

Common Triggers:

• Irritants: Soaps, cleaning agents, acids, or alkalis.
• Allergens: Metals (nickel, cobalt), plants (poison ivy, oak), rubber, fragrances, or preservatives.