30 Common Skin Diseases: Causes, Symptoms and Treatment from a Dermatologist

There are about 3,000 skin diseases, but around 30 are commonly seen in dermatology clinics in Thailand. In this article, dermatologists have gathered the most common skin diseases, with a brief overview of their causes, symptoms and treatment approaches, as a basic reference guide. Accurate diagnosis and treatment should be under the care of a doctor.

The 20 Most Common Conditions

• 1. Acne: Hair follicles blocked by oil and C. acnes bacteria. Types include comedonal, inflammatory, hormonal and cystic acne. Treated with Retinoids, Benzoyl peroxide, Clindamycin, Spironolactone and Isotretinoin.

• 2. Melasma: Increased Melanin pigment caused by sun exposure and hormones. Treated with Tranexamic acid, Hydroquinone, Pico Laser and SPF50+ sunscreen.

• 3. Atopic Dermatitis: A chronic condition common in children, with severe itching. Treated with Moisturizer, Topical Steroid, Tacrolimus, Dupilumab and NB-UVB.

• 4. Psoriasis: Caused by an abnormal immune response, with thick, silvery scaly patches. Treated with Vitamin D analog, biologics, NB-UVB and Methotrexate.

• 5. Seborrheic Dermatitis: Oily, flaky rash linked to Malassezia yeast. Treated with Ketoconazole shampoo and Tacrolimus.

• 6. Urticaria (hives): Itchy, raised red welts. Treated with Antihistamine, and Omalizumab in chronic cases.

• 7. Hair loss (Alopecia): Types include hereditary (AGA), patchy hair loss (Areata) and Telogen. Treated with Minoxidil, Finasteride, PRP and JAK inhibitors.

• 8. Warts: Caused by HPV infection. Treated with Cryotherapy, Salicylic acid, Electrocautery and lasers.

• 9. Herpes Simplex: Caused by the HSV-1 and HSV-2 viruses. Treated with Acyclovir and Valacyclovir.

• 10. Shingles (Herpes Zoster): Caused by reactivation of the VZV virus. Treated with antiviral medication within 72 hours, and a preventive vaccine is available (Shingrix).

• 11. Ringworm and tinea versicolor (Tinea): Caused by Dermatophyte fungi. Treated with topical or oral antifungal medication such as Terbinafine and Itraconazole.

• 12. Scabies: Caused by the Sarcoptes scabiei mite. Treated with Permethrin 5% and oral Ivermectin.

• 13. Post-inflammatory dark or red marks (PIH/PIE): Treated with Tranexamic acid, Azelaic acid, Pico Laser (for dark marks) and PDL/V-Beam (for red marks).

• 14. Rosacea: Facial redness with visible tiny blood vessels. Treated with Metronidazole, Ivermectin, PDL and Brimonidine.

• 15. Vitiligo: The immune system destroys pigment-producing cells. Treated with NB-UVB, Excimer, Tacrolimus and a JAK inhibitor (Ruxolitinib).

• 16. Skin Cancer: Includes BCC, SCC and Melanoma. The ABCDE rule is used for monitoring. Treated with surgery, Mohs surgery and Immunotherapy.

• 17. Keratosis Pilaris: Treated with Urea cream, Salicylic acid lotion and Tretinoin.

• 18. Keloid: Treated with steroid injections into the scar, 5-FU, PDL, and surgery combined with radiation therapy.

• 19. Skin tags and seborrheic keratosis: Include Skin tag and Seborrheic keratosis. Treated with Electrocautery, radiofrequency (RF) and lasers.

• 20. Dandruff: Treated with anti-dandruff shampoo containing Ketoconazole or Zinc pyrithione.

10 More Common Conditions

Other common skin diseases include 10 more: Contact dermatitis, Drug rash, Miliaria (heat rash), Impetigo, Mole (Nevus), Hyperpigmentation, Vitiligo, Hidradenitis Suppurativa, Hyperhidrosis and Xerosis (dry, cracked skin).

When Should You See a Dermatologist?

• Persistent rash: A rash that spreads quickly or does not clear within 2 weeks.

• Signs of infection: A rash with oozing, pus or severe pain.

• Suspected skin cancer: A mole or skin growth that enlarges quickly, changes color or has unclear borders (per the ABCDE rule).

• Accompanying symptoms: Systemic symptoms such as fever, joint pain or fatigue.

• Rash in children: A rash in a child that does not improve within 1 month.

Frequently Asked Questions

What are the most common skin diseases in Thailand? Common conditions include acne, melasma, atopic dermatitis, seborrheic dermatitis, tinea, urticaria and hair loss. Most can be controlled and treated with an appropriate approach.

Which rashes need prompt medical attention? A rash that spreads quickly, does not clear within 2 weeks, has oozing or pus, comes with fever, or a mole that changes according to the ABCDE rule should be seen by a doctor promptly.

Can most skin diseases be cured? Many skin diseases can be cured. Chronic conditions such as psoriasis or atopic dermatitis may not be cured completely, but symptoms can be well controlled with continued treatment.

Is a skin biopsy always necessary? Not every time. A biopsy is considered only when an abnormal lesion or skin cancer is suspected, to confirm the diagnosis.

If you have concerns or your symptoms do not improve, we recommend consulting a dermatologist for a diagnosis and a treatment plan suited to you. Consult a dermatologist at Siam Dermatology, call +66 61 448 7000 or LINE @siamderm

Written by Dr. Patara Voravutinon, Dermatologist · Last reviewed July 16, 2026