Dear Doctor
I have this small circle on my nose. It is swollen and has been like this for two weeks.
Dear Patient
Your picture is not very clear and so I will have to make some deductions.
The most common cause of round skin lesions on the skin is the fungal infection commonly referred to as ringworm or Tinea faciei when it affects the face or Tinea corporis when it is on the rest of the body. However, you say that the circle on your nose is swollen but in ringworms only the border is raised. I therefore advise you to have a KOH skin preparation test done. This is a painless procedure in which the lesion is scraped and the skin scrapings mixed with potassium hydroxide (KOH) and examined in the lab for the presence of fungal elements. If these are present, it is treated with antifungal creams like clotrimazole (Lotrimin) and terbinafine (Lamisil).
Tinea versicolor is another fungal infection which can cause round skin lesions on the face as you can see from the picture below. These lesion are hypopigmented (lighter than the surrounding skin) in people with darker skin and pinkish in those with lighter skin. The diagnosis of Tinea versicolor is confirmed by doing a KOH skin preparation and it is also treated with antifungals.
Leprosy or Hansen’s disease is another condition which can cause round skin lesions. These patches are hypopigmented, have reduced sensation and usually develop on cooler parts of the body like the ears and nose. A skin biopsy can be done to confirm the diagnosis of leprosy which is treated with multiple antibiotics like dapsone and rifampicin.
Vitiligo is another condition which can cause roundish, white spots on the skin as seen in the picture below. Though the diagnosis of Vitiligo can be made clinically after the doctor listens to the symptoms and examines the skin, a skin biopsy can also be done to confirm the absence of melanocytes which are the cells that produce the skin pigment melanin.
Sarcoidosis is another condition which can affect the skin and cause round lesions which may appear swollen due to infiltration. However sarcoidosis lesions are usually reddish brown in color while that one on your nose looks whitish. A skin biopsy can be done to confirm the diagnosis of sarcoidosis. There is no cure for sarcoidosis but corticosteroids can be applied or injected into the skin lesions.
Discoid lupus erythematosus (DLE) can also present with annular lesions on the face which heal with scarring. The lesions are scaly and their centers are usually lighter than the surrounding hyperpigmented active areas. Some patients with DLE also have symptoms of systemic lupus erythematosus (SLE) like joint pains, fever and fatigue. A skin biopsy can be done as well as screening tests for SLE like renal function tests. Treatment includes the application of sunscreen and steroids and the use of antimalarials like hydroxychloroquine.
In view of all these differential diagnoses for annular lesions on the face, I would request that you send us a focused close up photo of that circular lesion on your nose.
