Secondary Syphilis rash?

Age: 29 Sex: Male Medications: None currently Duration of symptoms: ~9-10weeks Existing medical issues: None

Hi, I’ve been dealing with some persistent but confusing symptoms for about 10 weeks and would appreciate your input.

First symptom: (18 days after exposure - receptive oral sex) • Located on dorsal side of the penis • Not painful • A scab that fell off the same day and revealed a plaque/ulcer like change which lasted for 3 weeks and healed with pink scar. • ~4-5 mm in diameter

Other symptoms: (33-34 days after exposure) • Pain in cervical lymph nodes
• A faint rash on chest and abdomen • Burning tongue feeling

My first thoughtwas: Definitely Syphilis. So I tested at 36 days with treponemal EIA which was negative, and then went on Doxycycline: 2x daily for 14 days 100mg.
4 days into Doxy all symptoms dissapeared, but all came back 2 weeks after the last dose.

I retested at 10 and 12 weeks with TPHA and TP ECLIA. Both came out negative. At 12 weeks additional tests were done:

•	HIV 4th gen: negative
•	HBsAg: negative
•	HCV Ab: negative
•     NG/CT/Ureaplasma,Micoplasma: neg.

Additionaly, my complete CBC with Liver, Kidney, Thyroid and other markers is normal.

Summary of symptoms:

Main symptoms now: • Mild, diffuse, non-itchy red rash on chest/torso • Rash comes and goes throughout the day (sometimes almost invisible) • No scaling, no bumps, not raised, normal texture • Rash completely resolved while taking doxycycline for 2 weeks, but returned ~2 weeks after stopping • Rash has not gotten worse, just fluctuates

Lymph nodes: • Two lymph nodes under the jaw intermittently swell with pain • Not constantly enlarged • Often normal in the morning • No generalized lymphadenopathy

Mouth/tongue: • Occasional burning/tingling of the tongue and palate • Tongue looks normal

Other symptoms: • No fever, no night sweats, no fatigue, no weight loss • No sore throat, no other systemic symptoms

Do I need to retest, or look into other possibilities?