Dermatology� July 31, 2026� 9 min read

Skin Conditions Explained: Acne, Eczema, and Common Rashes

Medically Reviewed by Dr. Marcus Chen, Dermatology, Stanford Medicine on July 31, 2026. Adheres to strict medical communication criteria.

Dr. Hannah Lee, MD, FAAD

Dermatologist, NYU Langone at Premedice Systems

Summary & Key Takeaway

Skin conditions are disorders affecting the skin � the body's largest organ � including acne, eczema, psoriasis, rosacea, and contact dermatitis, each with distinct causes and treatment approaches. They're among the most common reasons people see a doctor � and for good reason. Your skin is your body's largest organ, and when something goes wrong, it's visible, uncomfortable, and often affects your self-esteem. Acne affects 50 million Americans annually. Eczema (atopic dermatitis) affects 31 million. Psoriasis affects 7.5 million. And these are just the big three. The good news: dermatology has made remarkable advances in treating skin conditions, with biologic therapies, targeted topicals, and laser treatments transforming outcomes for conditions that were once difficult to manage. The key is proper diagnosis � because many skin conditions look similar but require very different treatments. [Premedice](/) can help you evaluate your skin symptoms and determine whether dermatology referral is warranted.

?? Core Insights

Acne is caused by four factors: excess oil production, clogged pores, bacteria (C. acnes), and inflammation � effective treatment targets all four simultaneously
Eczema (atopic dermatitis) is a barrier defect in the skin � treatments focus on restoring the skin barrier (moisturizers), reducing inflammation (topical steroids, calcineurin inhibitors), and controlling itch
Psoriasis is an autoimmune condition � new biologic therapies (TNF inhibitors, IL-17 inhibitors, IL-23 inhibitors) have transformed treatment, achieving clear skin in 70�90% of patients
Rosacea is a chronic facial flushing condition triggered by heat, alcohol, spicy foods, and sun � topical metronidazole, azelaic acid, and oral doxycycline are first-line treatments
Contact dermatitis (allergic or irritant) is diagnosed by identifying the trigger � patch testing identifies specific allergens, and avoidance is the only definitive treatment. [Premedice](/) can help you evaluate your skin symptoms and determine the most appropriate treatment approach

Acne: More Than Just Pimples

Acne is the most common skin condition in the United States, affecting up to 50 million people. It occurs when hair follicles become clogged with oil (sebum) and dead skin cells. The bacterium Cutibacterium acnes (formerly Propionibacterium acnes) thrives in this environment, triggering inflammation that produces the red, swollen bumps we recognize as pimples. Acne severity ranges from comedones (blackheads and whiteheads, non-inflammatory) to papules, pustules, nodules, and cysts (inflammatory). Hormonal factors � particularly androgens � increase sebum production, which is why acne often flares during puberty, menstruation, and pregnancy.

Effective acne treatment requires targeting multiple factors simultaneously. For mild acne (comedones and few papules), topical retinoids (adapalene/Differin, tretinoin, tazarotene) are first-line � they normalize skin cell turnover, preventing clogged pores, and have anti-inflammatory properties. Benzoyl peroxide kills C. acnes bacteria and reduces inflammation. For moderate-to-severe acne, oral antibiotics (doxycycline, minocycline) reduce bacteria and inflammation. Hormonal treatments (combined oral contraceptives, spironolactone) are effective for women with hormonal acne patterns (jawline, chin, cyclic flares). Isotretinoin (Accutane) is the most effective treatment for severe or treatment-resistant acne, addressing all four pathogenic factors. Newer topical treatments like trifarotene (a retinoid targeting both acne and inflammation) and clascoterone (a topical anti-androgen) provide additional options.

Eczema: When Your Skin Barrier Breaks Down

Eczema (atopic dermatitis) is fundamentally a skin barrier disorder. People with eczema have a genetically impaired skin barrier (often due to filaggrin deficiency) that loses moisture more easily and allows irritants and allergens to penetrate, triggering an immune response. This creates the characteristic cycle: dry, compromised skin ? irritant/allergen penetration ? immune activation ? inflammation ? itch ? scratching ? further barrier damage ? more inflammation. Eczema typically begins in infancy or childhood (affecting up to 20% of children) but can persist or begin in adulthood.

Treatment focuses on breaking this cycle. The foundation is skin barrier repair: regular application of emollients (moisturizers) � ideally within 3 minutes of bathing (the 'soak and seal' method) � maintains hydration and creates a protective layer. Topical corticosteroids (hydrocortisone, triamcinolone, clobetasol, in increasing potency) reduce inflammation during flares and should be used proactively (twice weekly on previously affected areas) to prevent recurrence. For steroid-sparing maintenance, topical calcineurin inhibitors (tacrolimus, pimecrolimus) and topical PDE4 inhibitors (crisaborole/Eucrisa) reduce inflammation without steroid side effects. For moderate-to-severe eczema, biologic therapies � dupilumab (Dupixent) and tralokinumab (Adbry) � block the IL-4/IL-13 inflammatory pathway and have transformed outcomes, achieving clear or almost clear skin in 40�60% of patients. JAK inhibitors (abrocitinib, upadacitinib) are oral alternatives for those who prefer pills over injections.

Psoriasis: Autoimmune Skin Disease

Psoriasis is an autoimmune condition in which the immune system attacks skin cells, causing them to multiply too rapidly � skin cell turnover accelerates from the normal 28�30 days to just 3�5 days. The result is thick, scaly plaques (silvery-white on a red base) typically found on elbows, knees, scalp, and lower back. About 30% of people with psoriasis develop psoriatic arthritis, causing joint pain, stiffness, and swelling. Psoriasis is also associated with increased cardiovascular risk, metabolic syndrome, and depression.

Treatment has been revolutionized by biologic therapies. For mild psoriasis, topical treatments (corticosteroids, vitamin D analogues like calcipotriene, retinoids like tazarotene) are effective. For moderate-to-severe psoriasis, phototherapy (narrowband UVB light) is highly effective and safe. Systemic medications include methotrexate, cyclosporine, and acitretin. Biologic therapies � which target specific immune pathways � are the most significant advance. TNF inhibitors (adalimumab/Humira, etanercept/Enbrel), IL-17 inhibitors (secukinumab/Cosentyx, ixekizumab/Taltz), and IL-23 inhibitors (guselkumab/Tremfya, risankizumab/Skyrizi) achieve PASI 75 (75% improvement) in 70�90% of patients, with many achieving clear or almost clear skin. IL-23 inhibitors, in particular, offer long dosing intervals (every 8�12 weeks) and favorable safety profiles.

Rosacea and Contact Dermatitis

Rosacea is a chronic inflammatory condition affecting the face, characterized by persistent redness (erythema), flushing, visible blood vessels (telangiectasia), and sometimes pustules or papules (which can mimic acne). Subtype 2 (papulopustular rosacea) is the most common and most treatable. Triggers include sun exposure, heat, alcohol, spicy foods, stress, and hot beverages. Treatment includes topical metronidazole, azelaic acid, and ivermectin for mild-to-moderate rosacea, and low-dose oral doxycycline (40 mg modified-release) for moderate-to-severe cases. Intense pulsed light (IPL) and vascular lasers treat visible blood vessels and persistent redness.

Contact dermatitis comes in two forms: allergic (a delayed hypersensitivity reaction to a specific allergen, like nickel in jewelry, fragrance in cosmetics, or poison ivy) and irritant (direct damage to the skin from a chemical or physical agent, like harsh soaps or frequent hand washing). Diagnosis involves identifying the trigger � patch testing (applying small amounts of common allergens to the back and reading results at 48 and 96 hours) identifies specific allergic triggers. Treatment is avoidance of the trigger plus topical steroids to reduce inflammation. For hand dermatitis (the most common form), barrier repair (frequent moisturizing, wearing gloves for wet work) is essential for prevention.

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About the Author

Dr. Hannah Lee, MD, FAAD

Dr. Lee is a board-certified dermatologist with expertise in inflammatory skin conditions and medical dermatology.

Expert Takeaway

Most common skin conditions are highly treatable with proper diagnosis and appropriate therapy. Acne, eczema, psoriasis, and rosacea each have specific treatment algorithms. Don't suffer in silence � effective treatments exist for virtually every common skin condition.

QFrequently Asked Questions

Q1Is acne caused by dirty skin?

No. Acne is caused by excess oil production, clogged pores, bacteria, and inflammation � not by dirt on the skin surface. Over-washing or scrubbing the skin can actually worsen acne by irritating the skin and disrupting the skin barrier. Gentle cleansing twice daily with a mild cleanser is recommended. Acne is a medical condition, not a hygiene problem.

Q2Will eczema go away?

Many children outgrow eczema � about 60% improve significantly by adolescence. However, eczema can persist into adulthood or begin in adulthood. There is no cure for eczema, but it can be effectively managed with consistent skin care (moisturizing, avoiding triggers) and appropriate medications. Newer biologic therapies have dramatically improved outcomes for moderate-to-severe cases.

Q3Is psoriasis contagious?

No. Psoriasis is an autoimmune condition � it cannot be spread through touch, sharing personal items, or any form of contact. Psoriasis is caused by your own immune system attacking skin cells, not by an infection. The visible plaques can be embarrassing, but they pose no risk to others.

Q4How is rosacea different from acne?

Rosacea and acne share some features (redness, bumps) but are different conditions. Rosacea typically affects adults over 30 (not teenagers), causes persistent facial redness and flushing (acne does not), lacks blackheads/whiteheads (acne's hallmark), and can affect the eyes (ocular rosacea). Acne is characterized by comedones (blackheads/whiteheads), affects younger populations, and doesn't cause persistent redness between breakouts.

Q5Can AI help diagnose skin conditions?

AI image analysis tools can help identify common skin conditions based on photos, track changes in skin lesions over time, and recommend whether dermatology referral is needed. Premedice can help you evaluate your skin symptoms, determine whether your condition warrants dermatology consultation, and track treatment response over time.